feat(snapshot): re-encode captures + disk-pressure retention

Camera snapshots were stored RAW — the camera's full-res JPEG straight into
the BLOB, no resize/recompress. Measured on the dev DB: 300 snapshots = 81.7 MB
= ~72% of the 114 MB SQLite file (the big ones 2688×1520 / ~600 KB, Hikvision
main stream). They dominated the appliance's single backed-up DB file.

Re-encode on capture (snapshot.ts):
- Downscale each frame to SNAPSHOT_MAX_EDGE (1280px long edge) + recompress at
  SNAPSHOT_JPEG_QUALITY (80) via sharp (libvips, Apache-2.0) before storage —
  ~6-10× smaller (verified 2688×1520 → 1280×724, ~8×), plate still readable,
  clean image/jpeg (drops the camera's charset cruft). STORAGE-ONLY: recognition
  keeps the ORIGINAL full-res bytes (downscaling hurts OCR). Fail-soft — a
  re-encode error stores the original, never drops the snapshot or blocks the
  (already-open) path. sharp lives in apps/server (owns the capture path), where
  bcrypt already establishes the native-dep pattern.

Disk-pressure retention (snapshot-retention.ts) — a SAFETY VALVE, not the daily
mechanism (the re-encode does that). Daily check reads the DB filesystem used%
(statfs on db.$client.name); no-op unless ≥ SNAPSHOT_DISK_HIGH_PCT (70). Over the
mark: delete the OLDEST until an estimated SNAPSHOT_DISK_FREE_TARGET_PCT (10%) of
disk is freed — never below SNAPSHOT_MIN_KEEP (500) — then VACUUM once to return
space to the OS. A DELETE only frees SQLite pages (disk doesn't drop until VACUUM),
so the loop is driven by estimated freed bytes (SUM(length(bytes))), not a live
disk re-read; the prune owns the DB-locking VACUUM, run daily off-peak. diskUsage
is injectable for tests. None of this touches the signed ledger — snapshots are
unsigned/advisory, referenced only by id.

Tests: encodeForStorage (downscale / clean-type / no-enlarge / fail-soft) +
pruneSnapshots (no-op below mark / delete-oldest-to-target + VACUUM / MIN_KEEP
floor / skip-VACUUM-when-empty). All four snapshot env knobs documented in the
komodo env reference. Full workspace build/lint/test green; the prune smoke-verified
on a scratch DB copy (file shrank after VACUUM).

Existing ~81.7 MB of raw snapshots are unchanged (a one-off re-encode backfill is
a separate optional follow-up). Updated entry-exit-points + technology-stack wiki.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/server/package.json

@@ -23,7 +23,8 @@
     "@parking/shared": "workspace:*",
     "bcrypt": "6.0.0",
     "fastify": "5.8.5",
-    "fastify-plugin": "6.0.0"
+    "fastify-plugin": "6.0.0",
+    "sharp": "^0.35.2"
   },
   "devDependencies": {
     "@types/bcrypt": "6.0.0",

apps/server/src/server.ts

@@ -20,6 +20,7 @@ import { PrinterMonitor } from "./printer-monitor.js";
 import { DeviceMonitor } from "./device-monitor.js";
 import { buildSigner, buildVerifier } from "./signer.js";
 import { LogService, pinoDbStream } from "./log-service.js";
+import { pruneSnapshots } from "./snapshot-retention.js";
 import { logRoutes } from "./routes/logs.js";
 import { VisionClient } from "./vision-client.js";
 import { authRoutes } from "./routes/auth.js";
@@ -283,6 +284,23 @@ export async function buildServer(opts: BuildOptions = {}): Promise<FastifyInsta
   logService.prune(); // once at startup
   app.addHook("onClose", async () => clearInterval(pruneTimer));
 
+  // Snapshot retention prune — DISK-PRESSURE safety valve: only when the DB's filesystem
+  // crosses the high-water mark do we delete the oldest snapshots + VACUUM. A no-op the rest
+  // of the time. Daily, unref'd, plus once at startup. See snapshot-retention.ts.
+  const runSnapPrune = async () => {
+    const res = await pruneSnapshots(db, {}, app.log);
+    if (res.deletedRows > 0) {
+      app.log.info(
+        `pruned ${res.deletedRows} snapshots, freed ~${(res.freedBytesEst / 1048576).toFixed(0)} MB ` +
+          `(disk was ${res.usedPctBefore.toFixed(0)}% used${res.vacuumed ? ", vacuumed" : ""})`,
+      );
+    }
+  };
+  const snapPruneTimer = setInterval(() => void runSnapPrune(), 24 * 60 * 60 * 1000);
+  snapPruneTimer.unref();
+  void runSnapPrune(); // once at startup
+  app.addHook("onClose", async () => clearInterval(snapPruneTimer));
+
   // Recycle-bin retention sweep: auto-purge master data soft-deleted longer than the
   // retention window (RECYCLE_BIN_RETENTION_DAYS, default 30; 0 = keep forever). Runs
   // every 6h, unref'd, plus once at startup. See recycle-bin.ts.

apps/server/src/snapshot-retention.test.ts

@@ -0,0 +1,96 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { snapshots, type Db } from "@parking/db";
+import { createTestDb } from "@parking/db/testing";
+import { pruneSnapshots, type DiskUsage, type SnapshotRetention } from "./snapshot-retention.js";
+
+// Snapshot retention: DISK-PRESSURE prune. No-op unless the DB's filesystem is over the
+// high-water mark; then delete the OLDEST until ~freeTargetPct of disk is freed (estimated from
+// the deleted BLOB sizes), honoring a MIN_KEEP floor, then VACUUM once. Disk usage is injected
+// so the test controls the trigger without touching the real filesystem.
+
+let db: Db;
+beforeEach(() => {
+  ({ db } = createTestDb());
+});
+
+/** Insert `n` snapshots, oldest first (s-0 is the oldest), each `bytes` long. */
+function seed(n: number, bytes = 1000): void {
+  const t0 = Date.now() - n * 1000;
+  for (let i = 0; i < n; i++) {
+    db.insert(snapshots)
+      .values({
+        id: `s-${i}`,
+        direction: "entry",
+        deviceId: "cam",
+        identity: `s-${i}`,
+        contentType: "image/jpeg",
+        bytes: Buffer.alloc(bytes, 1),
+        capturedAt: new Date(t0 + i * 1000).toISOString(), // s-0 oldest … s-(n-1) newest
+      })
+      .run();
+  }
+}
+
+function count(): number {
+  return db.select().from(snapshots).all().length;
+}
+function ids(): string[] {
+  return db.select().from(snapshots).all().map((r) => r.id).sort();
+}
+
+/** A fake disk at a given used% on a 1 GB volume. */
+const disk = (usedPct: number, totalBytes = 1_000_000_000): (() => Promise<DiskUsage>) =>
+  () => Promise.resolve({ usedPct, totalBytes });
+
+const ret = (o: Partial<SnapshotRetention>): SnapshotRetention => ({
+  highPct: 70,
+  freeTargetPct: 10,
+  minKeep: 2,
+  batch: 5,
+  ...o,
+});
+
+describe("pruneSnapshots (disk-pressure)", () => {
+  it("no-op when disk is below the high-water mark", async () => {
+    seed(10);
+    const res = await pruneSnapshots(db, { retention: ret({}), diskUsage: disk(50) });
+    expect(res.deletedRows).toBe(0);
+    expect(res.vacuumed).toBe(false);
+    expect(count()).toBe(10);
+  });
+
+  it("over the mark: deletes the OLDEST until ~freeTargetPct is freed, then VACUUMs", async () => {
+    // 1 GB disk, target 10% = 100 MB. Each snapshot 20 MB → ~5 deletions reach the target.
+    seed(20, 20 * 1048576);
+    const vacuumSpy = vi.spyOn(db.$client as { exec: (s: string) => void }, "exec");
+    const res = await pruneSnapshots(db, { retention: ret({ minKeep: 2, batch: 100 }), diskUsage: disk(80) });
+    expect(res.deletedRows).toBeGreaterThanOrEqual(5);
+    expect(res.freedBytesEst).toBeGreaterThanOrEqual(0.1 * 1_000_000_000);
+    expect(res.vacuumed).toBe(true);
+    expect(vacuumSpy).toHaveBeenCalledWith("VACUUM");
+    // The survivors are the NEWEST (oldest went first).
+    const survivors = ids();
+    expect(survivors).toContain(`s-19`); // newest kept
+    expect(survivors).not.toContain(`s-0`); // oldest pruned
+    vacuumSpy.mockRestore();
+  });
+
+  it("honors the MIN_KEEP floor even when still over target", async () => {
+    // Target 10% of 1 GB = 100 MB, but only 3 tiny snapshots exist and minKeep=2 → at most 1 deleted.
+    seed(3, 1000);
+    const res = await pruneSnapshots(db, { retention: ret({ minKeep: 2, freeTargetPct: 90 }), diskUsage: disk(95) });
+    expect(res.deletedRows).toBe(1); // 3 − minKeep(2)
+    expect(count()).toBe(2);
+    expect(res.floorHitWhileOver).toBe(true); // couldn't reach target without crossing the floor
+  });
+
+  it("skips VACUUM when nothing was deleted", async () => {
+    seed(2); // == minKeep, so nothing to delete even over the mark
+    const vacuumSpy = vi.spyOn(db.$client as { exec: (s: string) => void }, "exec");
+    const res = await pruneSnapshots(db, { retention: ret({ minKeep: 2 }), diskUsage: disk(99) });
+    expect(res.deletedRows).toBe(0);
+    expect(res.vacuumed).toBe(false);
+    expect(vacuumSpy).not.toHaveBeenCalled();
+    vacuumSpy.mockRestore();
+  });
+});

apps/server/src/snapshot-retention.ts

@@ -0,0 +1,148 @@
+import { statfs } from "node:fs/promises";
+import { dirname, resolve } from "node:path";
+import { asc, snapshots, sql, type Db } from "@parking/db";
+import type { FastifyBaseLogger } from "fastify";
+
+// Snapshot retention — DISK-PRESSURE model. Camera snapshots are unsigned, advisory, prunable
+// BLOBs (see snapshot.ts); they're referenced by the signed ledger only by id, so pruning an
+// old image never affects the chain. They no longer dominate the DB day-to-day (captures are
+// re-encoded small at SNAPSHOT_MAX_EDGE/JPEG_QUALITY), so this is a SAFETY VALVE: only when the
+// filesystem holding the DB crosses a high-water mark do we delete the OLDEST snapshots and
+// VACUUM to return disk to the OS.
+//
+// Why estimated-bytes, not live disk%: a DELETE only frees SQLite *pages* — the file (and thus
+// OS disk usage) doesn't shrink until VACUUM. So the prune loop can't watch usedPct fall in real
+// time. Instead it sums LENGTH(bytes) of the rows it deletes and stops when that estimate reaches
+// the free-target, then VACUUMs ONCE at the end to realize the space. A MIN_KEEP floor always
+// wins — we never delete evidence below it, even under pressure (if the disk is full of something
+// else, that's not ours to fix).
+
+export interface SnapshotRetention {
+  /** Prune when the DB's filesystem is at least this % used. */
+  readonly highPct: number;
+  /** Try to free roughly this % of the disk per run (the delete target). */
+  readonly freeTargetPct: number;
+  /** Never prune below this many snapshots (the floor). */
+  readonly minKeep: number;
+  /** Delete oldest in batches of this size (re-checks between batches). */
+  readonly batch: number;
+}
+
+export const DEFAULT_SNAPSHOT_RETENTION: SnapshotRetention = {
+  highPct: Number(process.env.SNAPSHOT_DISK_HIGH_PCT ?? 70),
+  freeTargetPct: Number(process.env.SNAPSHOT_DISK_FREE_TARGET_PCT ?? 10),
+  minKeep: Number(process.env.SNAPSHOT_MIN_KEEP ?? 500),
+  batch: Number(process.env.SNAPSHOT_PRUNE_BATCH ?? 200),
+};
+
+/** Disk usage of the filesystem holding the DB. Injectable so tests don't touch the real FS. */
+export interface DiskUsage {
+  readonly usedPct: number;
+  readonly totalBytes: number;
+}
+
+export interface PruneOptions {
+  readonly retention?: SnapshotRetention;
+  /** Override how disk usage is read (tests inject a fake; default = statfs the DB's FS). */
+  readonly diskUsage?: () => Promise<DiskUsage>;
+}
+
+export interface PruneResult {
+  readonly deletedRows: number;
+  readonly freedBytesEst: number;
+  readonly vacuumed: boolean;
+  readonly usedPctBefore: number;
+  /** True if we hit the MIN_KEEP floor while the disk was still over the high-water mark. */
+  readonly floorHitWhileOver: boolean;
+}
+
+/** Read the used% + total bytes of the filesystem holding the DB file. */
+async function diskUsageForDb(db: Db): Promise<DiskUsage> {
+  const file = (db.$client as { name?: string }).name ?? process.env.DATABASE_URL ?? "./parking.sqlite";
+  const st = await statfs(dirname(resolve(file)));
+  const total = st.blocks * st.bsize;
+  const avail = st.bavail * st.bsize;
+  const usedPct = total > 0 ? (1 - avail / total) * 100 : 0;
+  return { usedPct, totalBytes: total };
+}
+
+/**
+ * Prune snapshots under DISK PRESSURE. No-op unless the DB's filesystem is ≥ highPct used. When
+ * over, deletes the OLDEST snapshots until an estimated freeTargetPct of the disk is freed (or the
+ * minKeep floor is hit, or no rows remain), then VACUUMs once. Best-effort; safe on a timer.
+ */
+export async function pruneSnapshots(
+  db: Db,
+  opts: PruneOptions = {},
+  logger?: FastifyBaseLogger,
+): Promise<PruneResult> {
+  const r = opts.retention ?? DEFAULT_SNAPSHOT_RETENTION;
+  const readDisk = opts.diskUsage ?? (() => diskUsageForDb(db));
+
+  let usedPctBefore = 0;
+  try {
+    const disk = await readDisk();
+    usedPctBefore = disk.usedPct;
+
+    // The overwhelmingly common case: plenty of headroom → do nothing.
+    if (disk.usedPct < r.highPct) {
+      return { deletedRows: 0, freedBytesEst: 0, vacuumed: false, usedPctBefore, floorHitWhileOver: false };
+    }
+
+    // Target bytes to free this run (≈ freeTargetPct of the whole disk).
+    const targetBytes = (r.freeTargetPct / 100) * disk.totalBytes;
+
+    let freedBytesEst = 0;
+    let deletedRows = 0;
+    let floorHitWhileOver = false;
+
+    // Delete the oldest in batches, summing their BLOB sizes, until we've freed the target — or
+    // we'd cross the MIN_KEEP floor — or there are no more rows.
+    for (;;) {
+      const count = db.select({ c: sql<number>`count(*)` }).from(snapshots).get()?.c ?? 0;
+      if (count <= r.minKeep) {
+        floorHitWhileOver = true; // still over the high-water mark but can't delete below the floor
+        break;
+      }
+      if (freedBytesEst >= targetBytes) break;
+
+      const room = count - r.minKeep; // how many we may still delete before the floor
+      const take = Math.min(r.batch, room);
+      const oldest = db
+        .select({ id: snapshots.id, len: sql<number>`length(${snapshots.bytes})` })
+        .from(snapshots)
+        .orderBy(asc(snapshots.capturedAt))
+        .limit(take)
+        .all();
+      if (oldest.length === 0) break;
+
+      const ids = oldest.map((o) => o.id);
+      db.delete(snapshots).where(sql`${snapshots.id} in (${sql.join(ids, sql`, `)})`).run();
+      deletedRows += oldest.length;
+      freedBytesEst += oldest.reduce((s, o) => s + (o.len ?? 0), 0);
+    }
+
+    // Realize the freed space: VACUUM returns pages to the OS (the file shrinks). Only if we
+    // actually deleted something. Non-fatal on failure — pages are still freed for reuse.
+    let vacuumed = false;
+    if (deletedRows > 0) {
+      try {
+        (db.$client as { exec: (sql: string) => void }).exec("VACUUM");
+        vacuumed = true;
+      } catch (err) {
+        logger?.warn(`snapshot prune: VACUUM failed (pages freed for reuse): ${(err as Error).message}`);
+      }
+    }
+
+    if (floorHitWhileOver) {
+      logger?.warn(
+        `snapshot prune: disk ${usedPctBefore.toFixed(0)}% used but hit MIN_KEEP floor (${r.minKeep}) ` +
+          `after deleting ${deletedRows} — disk pressure is not from snapshots`,
+      );
+    }
+    return { deletedRows, freedBytesEst, vacuumed, usedPctBefore, floorHitWhileOver };
+  } catch (err) {
+    logger?.warn(`snapshot prune failed: ${(err as Error).message}`);
+    return { deletedRows: 0, freedBytesEst: 0, vacuumed: false, usedPctBefore, floorHitWhileOver: false };
+  }
+}

apps/server/src/snapshot.test.ts

@@ -1,6 +1,8 @@
 import { describe, expect, it, vi } from "vitest";
+import sharp from "sharp";
 import type { CameraDevice, Snapshot } from "@parking/devices";
-import { captureSnapshotShared } from "./snapshot.js";
+import { captureSnapshotShared, encodeForStorage } from "./snapshot.js";
+import { silentLogger } from "./test-helpers.js";
 
 // captureSnapshotShared: one HTTP pull per camera per vehicle. A Hikvision unit serves
 // snapshots SINGLE-THREADED (a 2nd concurrent GET → HTTP 503). On an entry the ANPR
@@ -91,3 +93,49 @@ describe("captureSnapshotShared", () => {
     expect(s1.bytes.equals(s2.bytes)).toBe(false);
   });
 });
+
+// encodeForStorage: downscale + re-compress a captured frame for STORAGE (smaller, plate
+// still readable). Recognition uses the original; this never runs on the OCR path. Fail-soft.
+describe("encodeForStorage", () => {
+  /** A big synthetic JPEG (2688×1520, the Hikvision main-stream size) to downscale. */
+  async function bigJpeg(): Promise<Buffer> {
+    return sharp({
+      create: { width: 2688, height: 1520, channels: 3, background: { r: 120, g: 130, b: 140 } },
+    })
+      .jpeg({ quality: 95 })
+      .toBuffer();
+  }
+
+  it("downscales the long edge to ≤1280 and emits clean image/jpeg", async () => {
+    const bytes = await bigJpeg();
+    const shot: Snapshot = { bytes, contentType: 'image/jpeg; charset="UTF-8"', capturedAt: new Date().toISOString() };
+    const out = await encodeForStorage(shot, silentLogger());
+    expect(out.contentType).toBe("image/jpeg"); // charset cruft stripped
+    const meta = await sharp(out.bytes).metadata();
+    expect(Math.max(meta.width ?? 0, meta.height ?? 0)).toBeLessThanOrEqual(1280);
+    expect(out.bytes.length).toBeLessThan(bytes.length); // smaller than the original
+  });
+
+  it("never enlarges an already-small image", async () => {
+    const small = await sharp({ create: { width: 640, height: 360, channels: 3, background: { r: 0, g: 0, b: 0 } } })
+      .jpeg()
+      .toBuffer();
+    const out = await encodeForStorage(
+      { bytes: small, contentType: "image/jpeg", capturedAt: new Date().toISOString() },
+      silentLogger(),
+    );
+    const meta = await sharp(out.bytes).metadata();
+    expect(meta.width).toBe(640); // withoutEnlargement
+    expect(meta.height).toBe(360);
+  });
+
+  it("fails soft: a non-image body is stored unchanged with a cleaned type", async () => {
+    const garbage = Buffer.from("this is not an image");
+    const out = await encodeForStorage(
+      { bytes: garbage, contentType: 'text/plain; charset="UTF-8"', capturedAt: new Date().toISOString() },
+      silentLogger(),
+    );
+    expect(out.bytes.equals(garbage)).toBe(true); // original bytes, never dropped
+    expect(out.contentType).toBe("text/plain"); // charset stripped even on the fallback
+  });
+});

apps/server/src/snapshot.ts

@@ -1,4 +1,5 @@
 import { randomUUID } from "node:crypto";
+import sharp from "sharp";
 import { deviceEvents as deviceEventsTable, snapshots, type Db } from "@parking/db";
 import { registry, type CameraDevice, type Snapshot } from "@parking/devices";
 import type { FastifyBaseLogger } from "fastify";
@@ -27,6 +28,43 @@ import type { VisionClient } from "./vision-client.js";
 // fire-and-forget: it never blocks the open and never changes the entry/exit decision —
 // it's a record ("session X entered on plate AA558EE"). No polling; recognition only
 // happens on a real entry/exit. See wiki/entities/opencv-anpr-service.md.
+//
+// STORAGE RE-ENCODE (2026-06-28). Cameras serve full-res JPEGs (a Hikvision main stream is
+// 2688×1520 / ~600 KB); stored raw, snapshots dominated the appliance DB (~72%). Each frame
+// is now downscaled (long edge ≤ SNAPSHOT_MAX_EDGE) + re-compressed (q SNAPSHOT_JPEG_QUALITY)
+// BEFORE storage — ~6–10× smaller, plate still clearly readable. RECOGNITION runs on the
+// ORIGINAL full-res bytes (downscaling hurts OCR); the re-encode is storage-only. Fail-soft:
+// a re-encode error stores the original, never drops the snapshot or blocks the open.
+
+/** Long-edge cap (px) + JPEG quality for the STORED snapshot. Env-overridable per appliance. */
+const SNAP_MAX_EDGE = Number(process.env.SNAPSHOT_MAX_EDGE ?? 1280);
+const SNAP_QUALITY = Number(process.env.SNAPSHOT_JPEG_QUALITY ?? 80);
+
+/** Strip a camera's `; charset=...` cruft from a content type (a JPEG is binary). */
+function cleanType(ct: string): string {
+  const base = ct.split(";")[0]?.trim();
+  return base || "image/jpeg";
+}
+
+/** Downscale + re-encode a captured frame for STORAGE (evidence, not OCR). Caps the long edge
+ *  and re-compresses to JPEG. Fail-soft: any error (e.g. a non-image body) returns the original
+ *  bytes with a cleaned content type, so a snapshot is never lost. */
+export async function encodeForStorage(
+  shot: Snapshot,
+  logger: FastifyBaseLogger,
+): Promise<{ bytes: Buffer; contentType: string }> {
+  try {
+    const out = await sharp(shot.bytes, { failOn: "none" })
+      .rotate() // honor EXIF orientation before we drop the metadata
+      .resize({ width: SNAP_MAX_EDGE, height: SNAP_MAX_EDGE, fit: "inside", withoutEnlargement: true })
+      .jpeg({ quality: SNAP_QUALITY, mozjpeg: true })
+      .toBuffer();
+    return { bytes: out, contentType: "image/jpeg" };
+  } catch (err) {
+    logger.warn(`snapshot re-encode failed, storing original: ${(err as Error).message}`);
+    return { bytes: shot.bytes, contentType: cleanType(shot.contentType) };
+  }
+}
 
 interface SnapshotJob {
   readonly db: Db;
@@ -67,14 +105,17 @@ export function snapshotAsync(job: SnapshotJob): Promise<string[]> {
         // same vehicle, reuse it instead of a 2nd concurrent GET (which 503s).
         const shot = await captureSnapshotShared(row.id, camera, { direction });
         const id: string = randomUUID();
+        // Re-encode for STORAGE only (downscale + recompress). Recognition below still
+        // uses the original full-res `shot`.
+        const stored = await encodeForStorage(shot, logger);
         db.insert(snapshots)
           .values({
             id,
             direction,
             deviceId: row.id,
             identity,
-            contentType: shot.contentType,
-            bytes: shot.bytes,
+            contentType: stored.contentType,
+            bytes: stored.bytes,
             capturedAt: shot.capturedAt,
           })
           .run();

komodo/.env.komodo.example

@@ -60,6 +60,14 @@ WS_ALLOWED_ORIGINS=
 # LOG_RETENTION_DAYS=30              # app_logs auto-purge age
 # LOG_RETENTION_MAX_ROWS=50000      # app_logs row cap
 # RECYCLE_BIN_RETENTION_DAYS=30      # soft-deleted items auto-purge age (0 = keep forever)
+# --- snapshots (camera evidence; stored re-encoded, then pruned under disk pressure) ---
+# SNAPSHOT_MAX_EDGE=1280             # downscale long edge (px) before storing
+# SNAPSHOT_JPEG_QUALITY=80           # stored JPEG quality (recognition uses full-res original)
+# Disk-pressure prune (daily safety valve; deletes oldest + VACUUM only when the disk is tight):
+# SNAPSHOT_DISK_HIGH_PCT=70          # prune only when the DB's filesystem is ≥ this % used
+# SNAPSHOT_DISK_FREE_TARGET_PCT=10   # try to free ~this % of the disk per run
+# SNAPSHOT_MIN_KEEP=500              # never prune below this many snapshots (floor)
+# SNAPSHOT_PRUNE_BATCH=200           # delete oldest in batches of this many
 # --- device monitor / lane ---
 # DEVICE_POLL_MS=8000                # device health poll interval
 # PRINTER_POLL_MS=5000               # printer status poll interval

pnpm-lock.yaml

@@ -66,6 +66,9 @@ importers:
       fastify-plugin:
         specifier: 6.0.0
         version: 6.0.0
+      sharp:
+        specifier: ^0.35.2
+        version: 0.35.2
     devDependencies:
       '@types/bcrypt':
         specifier: 6.0.0
@@ -265,6 +268,9 @@ packages:
   '@emnapi/runtime@1.10.0':
     resolution: {integrity: sha512-ewvYlk86xUoGI0zQRNq/mC+16R1QeDlKQy21Ki3oSYXNgLb45GV1P6A0M+/s6nyCuNDqe5VpaY84BzXGwVbwFA==}
 
+  '@emnapi/runtime@1.11.1':
+    resolution: {integrity: sha512-vgj7R3y3Wgx24IQaGPA/R6YFXLHVMOZ0uVEyIQPaWs+rd1AzfEMXlAC22FYwO1XkKR6NPsq7mUandH8oIRdZFw==}
+
   '@emnapi/wasi-threads@1.2.1':
     resolution: {integrity: sha512-uTII7OYF+/Mes/MrcIOYp5yOtSMLBWSIoLPpcgwipoiKbli6k322tcoFsxoIIxPDqW01SQGAgko4EzZi2BNv2w==}
 
@@ -774,6 +780,152 @@ packages:
   '@floating-ui/utils@0.2.11':
     resolution: {integrity: sha512-RiB/yIh78pcIxl6lLMG0CgBXAZ2Y0eVHqMPYugu+9U0AeT6YBeiJpf7lbdJNIugFP5SIjwNRgo4DhR1Qxi26Gg==}
 
+  '@img/colour@1.1.0':
+    resolution: {integrity: sha512-Td76q7j57o/tLVdgS746cYARfSyxk8iEfRxewL9h4OMzYhbW4TAcppl0mT4eyqXddh6L/jwoM75mo7ixa/pCeQ==}
+    engines: {node: '>=18'}
+
+  '@img/sharp-darwin-arm64@0.35.2':
+    resolution: {integrity: sha512-eEieHsMksAW4IiO5NzauESRl2D2qz3J/kwUxUrSfV06A93eEaRfMpHXyUb1mAqrR7i8U9A0GRqE9pjn6u1Jjpg==}
+    engines: {node: '>=20.9.0'}
+    cpu: [arm64]
+    os: [darwin]
+
+  '@img/sharp-darwin-x64@0.35.2':
+    resolution: {integrity: sha512-BaktuGPCeHJMARpodR8jK4uKiZrPAy9WrfQW0sdI37clracq8Bp01AYS3SZgi5FS/y5twa9t4+LIuuxQjqRrWw==}
+    engines: {node: '>=20.9.0'}
+    cpu: [x64]
+    os: [darwin]
+
+  '@img/sharp-freebsd-wasm32@0.35.2':
+    resolution: {integrity: sha512-YoAxdnd8hPUkvLHd3bWY+YA8nw3xM/RyRopYucNsWHVSan8NLVM3X2volsfoRDcXdUJPg6tXahSd7HXPK7lRnw==}
+    engines: {node: '>=20.9.0'}
+    os: [freebsd]
+
+  '@img/sharp-libvips-darwin-arm64@1.3.1':
+    resolution: {integrity: sha512-4V/M3roRMTYjiwZY9IOVQOE8OyeCxFAkYmyZDrZl51uOKjibm3oeEJ4WAmLxutAfzFbC9jqUiPs2gbnGflH+7g==}
+    cpu: [arm64]
+    os: [darwin]
+
+  '@img/sharp-libvips-darwin-x64@1.3.1':
+    resolution: {integrity: sha512-c0/DxItpJv2+dGhgycJBBgotdqruGYDvA79drdh0MD1dFpy7JzJ/PlXwi1H4rFf0eTy8tgbI91aHDnZIceY3jQ==}
+    cpu: [x64]
+    os: [darwin]
+
+  '@img/sharp-libvips-linux-arm64@1.3.1':
+    resolution: {integrity: sha512-JznefmcK9j1JKPz8AkQDh89kjojubyfOasWBPKfzMIhPwsgDy9evpE/naJTXXXmghS1iFwR8u/kTwh/I2/+GCw==}
+    cpu: [arm64]
+    os: [linux]
+
+  '@img/sharp-libvips-linux-arm@1.3.1':
+    resolution: {integrity: sha512-aGGy9aWzXgHBG7HNyQPWorZthlp7+x6fDRoPAQbGO3ThcttuTyKIx3NuSHb6zb4gBNq6/yNn9f1cy9nFKS/Vmg==}
+    cpu: [arm]
+    os: [linux]
+
+  '@img/sharp-libvips-linux-ppc64@1.3.1':
+    resolution: {integrity: sha512-1EkwGNCZk6iWNCMWqrvdJ+r1j0PT1zIz60CNPhYnJlK/zyeWqlsPZIe+ocBVqPF8k/Ssee/NCk+tE9Ryrko6ng==}
+    cpu: [ppc64]
+    os: [linux]
+
+  '@img/sharp-libvips-linux-riscv64@1.3.1':
+    resolution: {integrity: sha512-Ilays+w2bXdnxzxtQdmXR62u8o8GYa3eL4+Gr+1KiE4xperMZUslRaVPJwwPkzlHEjGfXAfRVAa/7CYCtSqsBw==}
+    cpu: [riscv64]
+    os: [linux]
+
+  '@img/sharp-libvips-linux-s390x@1.3.1':
+    resolution: {integrity: sha512-VfBwVHQTbRoj4XlpA/KLZ7ltgMpz+4WSejFzQ+GnoImjo1PtEJ59QB2qR1xQEeRPYIkNrPIm2L4cICMvz4C2ew==}
+    cpu: [s390x]
+    os: [linux]
+
+  '@img/sharp-libvips-linux-x64@1.3.1':
+    resolution: {integrity: sha512-+c8ukgwU62DS54nCAjw7keOfHUkmr0B5QHEdcOqRnodF/MNXJbVI8Eopoj4B/0H8Asr65I+A4Amrn7a85/md6A==}
+    cpu: [x64]
+    os: [linux]
+
+  '@img/sharp-libvips-linuxmusl-arm64@1.3.1':
+    resolution: {integrity: sha512-qlKb/pwbkAi1WMsJrYHk7CuDrd12s27U2QnRhFYUoJNrRCmkosMTttuRFat/DDB3IlDm5qE1TJgZ4JDnHX8Ldw==}
+    cpu: [arm64]
+    os: [linux]
+
+  '@img/sharp-libvips-linuxmusl-x64@1.3.1':
+    resolution: {integrity: sha512-yO21HwoUVLN8Qa+/SBjQLMYwBWAVJjeGPNe+hc0OUeMeifEtJqu5a1c4HayE1nNpDih9y3/KkoltfkDodmKAlg==}
+    cpu: [x64]
+    os: [linux]
+
+  '@img/sharp-linux-arm64@0.35.2':
+    resolution: {integrity: sha512-af12Pnd0ZGu2HfP8NayB0kk6eC/lrfbQE6HlR4jD+34wdJ1Vw9TF6TMn6ZvffT+WgqVsl0hRbmNvz2u/23VmwA==}
+    engines: {node: '>=20.9.0'}
+    cpu: [arm64]
+    os: [linux]
+
+  '@img/sharp-linux-arm@0.35.2':
+    resolution: {integrity: sha512-SE4kzF2mepn6z+6E7L6lsV8FzuLL6IPQdyX8ZiwROAG/G8td+hP/m7FsFPwidtrF19gvajuC9l6TxAVcsA4S7A==}
+    engines: {node: '>=20.9.0'}
+    cpu: [arm]
+    os: [linux]
+
+  '@img/sharp-linux-ppc64@0.35.2':
+    resolution: {integrity: sha512-hYSBm7zcNtDCozCxQHYZJiu63b/bXsgRZuOxCIBZsStMM9Vap47iFHdbX4kCvQsblPB/k+clhELpdQJHQLSHvg==}
+    engines: {node: '>=20.9.0'}
+    cpu: [ppc64]
+    os: [linux]
+
+  '@img/sharp-linux-riscv64@0.35.2':
+    resolution: {integrity: sha512-qQt0Kc13+Hoan/Awq/qMSQw3L+RI1NCRPgD5cUJ/1WSSmIoysLOc72jlRM3E0OHN9Yr313jgeQ2T+zW+F03QFA==}
+    engines: {node: '>=20.9.0'}
+    cpu: [riscv64]
+    os: [linux]
+
+  '@img/sharp-linux-s390x@0.35.2':
+    resolution: {integrity: sha512-E4fLLfRPzDLlEeDaTzI98OFLcv++WL5ChLLMwPoVd0CIoZQqupBSNbOisPL5am9XsbQ9T84+iiMpUvbFtkunbA==}
+    engines: {node: '>=20.9.0'}
+    cpu: [s390x]
+    os: [linux]
+
+  '@img/sharp-linux-x64@0.35.2':
+    resolution: {integrity: sha512-gi0zFJJRLswfCZmHtJdikXPOc5u7qamSOS3NHedLqLd4W8Q0NqjdBr6TTRIgsfFjqfTsHFgdfvJ9LwqSgcHiAA==}
+    engines: {node: '>=20.9.0'}
+    cpu: [x64]
+    os: [linux]
+
+  '@img/sharp-linuxmusl-arm64@0.35.2':
+    resolution: {integrity: sha512-siWbOW1u6HFnFLrp0waKyW7VEf7jYvcDWdrXEFa8AkdAQgEvuu5Fz8/Y70w9EeqAdwDtfU012BhEHHaDqvQNzg==}
+    engines: {node: '>=20.9.0'}
+    cpu: [arm64]
+    os: [linux]
+
+  '@img/sharp-linuxmusl-x64@0.35.2':
+    resolution: {integrity: sha512-YBqMMcjDi4QGYiSn4vNOYBhmlC4z5AXqkOUUqI2e0AFA4urNv4ESgOgwNl3K+4etQhha0twXlzeF20bbULm9Yg==}
+    engines: {node: '>=20.9.0'}
+    cpu: [x64]
+    os: [linux]
+
+  '@img/sharp-wasm32@0.35.2':
+    resolution: {integrity: sha512-Mrv4JQNYVQ94xH+jzZ9r+gowleN8mv2FTgKT+PI6bx5C0G8TdNYndu161pg2i7uoBwxy2ImPMHrJOM2LZef7Bw==}
+    engines: {node: '>=20.9.0'}
+
+  '@img/sharp-webcontainers-wasm32@0.35.2':
+    resolution: {integrity: sha512-QNV27pxs9wpApEiCfvHM1RDoP1w1+2KrUWWDPEhEwg+latvOrfuhWrHWZKwdSFwU6jh3myjw/yOCRsUIuOft3g==}
+    engines: {node: '>=20.9.0'}
+    cpu: [wasm32]
+
+  '@img/sharp-win32-arm64@0.35.2':
+    resolution: {integrity: sha512-BiVRYc/t6/Vl3e1hBx0hugG4oN9Pydf4fgMSpxTQJmwGUg/YoXTWHiFeRymHfCZzifxu4F4rpk/I67D0LQ20wQ==}
+    engines: {node: '>=20.9.0'}
+    cpu: [arm64]
+    os: [win32]
+
+  '@img/sharp-win32-ia32@0.35.2':
+    resolution: {integrity: sha512-YYEhx9PImCC7T0tI8JDMi4DB9LwLCXCU5OWNYEXAxh5Q1ShKkyC6byxzoBJ3gEFDnH2lQckWuDe70G7mB2XJog==}
+    engines: {node: ^20.9.0}
+    cpu: [ia32]
+    os: [win32]
+
+  '@img/sharp-win32-x64@0.35.2':
+    resolution: {integrity: sha512-imoOyBcoM/iiUr4J6VPpCNjPnjvP/Gks95898yB8YqoGGYmHYbOyCuNv9FMhFgtaiHFGbHW8bxKqRV6VjtXThQ==}
+    engines: {node: '>=20.9.0'}
+    cpu: [x64]
+    os: [win32]
+
   '@jridgewell/gen-mapping@0.3.13':
     resolution: {integrity: sha512-2kkt/7niJ6MgEPxF0bYdQ6etZaA+fQvDcLKckhy1yIQOzaoKjBBjSj63/aLVjYE3qhRt5dvM+uUyfCg6UKCBbA==}
 
@@ -2576,6 +2728,10 @@ packages:
   setprototypeof@1.2.0:
     resolution: {integrity: sha512-E5LDX7Wrp85Kil5bhZv46j8jOeboKq5JMmYM3gVGdGH8xFpPWXUMsNrlODCrkoxMEeNi/XZIwuRvY4XNwYMJpw==}
 
+  sharp@0.35.2:
+    resolution: {integrity: sha512-FVtFjtBCMiJS6yb5CX7Sop45WFMpeGw6oRKuJnXYgf/f1ms/D7LE/ZUSNxnW7rZ/dbslQWYkoqFHGPaDBtaK4w==}
+    engines: {node: '>=20.9.0'}
+
   siginfo@2.0.0:
     resolution: {integrity: sha512-ybx0WO1/8bSBLEWXZvEd7gMW3Sn3JFlW3TvX1nREbDLRNQNaeNN8WK0meBwPdAaOI7TtRRRJn/Es1zhrrCHu7g==}
 
@@ -2953,6 +3109,11 @@ snapshots:
       tslib: 2.8.1
     optional: true
 
+  '@emnapi/runtime@1.11.1':
+    dependencies:
+      tslib: 2.8.1
+    optional: true
+
   '@emnapi/wasi-threads@1.2.1':
     dependencies:
       tslib: 2.8.1
@@ -3276,6 +3437,112 @@ snapshots:
 
   '@floating-ui/utils@0.2.11': {}
 
+  '@img/colour@1.1.0': {}
+
+  '@img/sharp-darwin-arm64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-darwin-arm64': 1.3.1
+    optional: true
+
+  '@img/sharp-darwin-x64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-darwin-x64': 1.3.1
+    optional: true
+
+  '@img/sharp-freebsd-wasm32@0.35.2':
+    dependencies:
+      '@img/sharp-wasm32': 0.35.2
+    optional: true
+
+  '@img/sharp-libvips-darwin-arm64@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-darwin-x64@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linux-arm64@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linux-arm@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linux-ppc64@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linux-riscv64@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linux-s390x@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linux-x64@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linuxmusl-arm64@1.3.1':
+    optional: true
+
+  '@img/sharp-libvips-linuxmusl-x64@1.3.1':
+    optional: true
+
+  '@img/sharp-linux-arm64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linux-arm64': 1.3.1
+    optional: true
+
+  '@img/sharp-linux-arm@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linux-arm': 1.3.1
+    optional: true
+
+  '@img/sharp-linux-ppc64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linux-ppc64': 1.3.1
+    optional: true
+
+  '@img/sharp-linux-riscv64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linux-riscv64': 1.3.1
+    optional: true
+
+  '@img/sharp-linux-s390x@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linux-s390x': 1.3.1
+    optional: true
+
+  '@img/sharp-linux-x64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linux-x64': 1.3.1
+    optional: true
+
+  '@img/sharp-linuxmusl-arm64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linuxmusl-arm64': 1.3.1
+    optional: true
+
+  '@img/sharp-linuxmusl-x64@0.35.2':
+    optionalDependencies:
+      '@img/sharp-libvips-linuxmusl-x64': 1.3.1
+    optional: true
+
+  '@img/sharp-wasm32@0.35.2':
+    dependencies:
+      '@emnapi/runtime': 1.11.1
+    optional: true
+
+  '@img/sharp-webcontainers-wasm32@0.35.2':
+    dependencies:
+      '@img/sharp-wasm32': 0.35.2
+    optional: true
+
+  '@img/sharp-win32-arm64@0.35.2':
+    optional: true
+
+  '@img/sharp-win32-ia32@0.35.2':
+    optional: true
+
+  '@img/sharp-win32-x64@0.35.2':
+    optional: true
+
   '@jridgewell/gen-mapping@0.3.13':
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.5
@@ -4910,6 +5177,38 @@ snapshots:
 
   setprototypeof@1.2.0: {}
 
+  sharp@0.35.2:
+    dependencies:
+      '@img/colour': 1.1.0
+      detect-libc: 2.1.2
+      semver: 7.8.4
+    optionalDependencies:
+      '@img/sharp-darwin-arm64': 0.35.2
+      '@img/sharp-darwin-x64': 0.35.2
+      '@img/sharp-freebsd-wasm32': 0.35.2
+      '@img/sharp-libvips-darwin-arm64': 1.3.1
+      '@img/sharp-libvips-darwin-x64': 1.3.1
+      '@img/sharp-libvips-linux-arm': 1.3.1
+      '@img/sharp-libvips-linux-arm64': 1.3.1
+      '@img/sharp-libvips-linux-ppc64': 1.3.1
+      '@img/sharp-libvips-linux-riscv64': 1.3.1
+      '@img/sharp-libvips-linux-s390x': 1.3.1
+      '@img/sharp-libvips-linux-x64': 1.3.1
+      '@img/sharp-libvips-linuxmusl-arm64': 1.3.1
+      '@img/sharp-libvips-linuxmusl-x64': 1.3.1
+      '@img/sharp-linux-arm': 0.35.2
+      '@img/sharp-linux-arm64': 0.35.2
+      '@img/sharp-linux-ppc64': 0.35.2
+      '@img/sharp-linux-riscv64': 0.35.2
+      '@img/sharp-linux-s390x': 0.35.2
+      '@img/sharp-linux-x64': 0.35.2
+      '@img/sharp-linuxmusl-arm64': 0.35.2
+      '@img/sharp-linuxmusl-x64': 0.35.2
+      '@img/sharp-webcontainers-wasm32': 0.35.2
+      '@img/sharp-win32-arm64': 0.35.2
+      '@img/sharp-win32-ia32': 0.35.2
+      '@img/sharp-win32-x64': 0.35.2
+
   siginfo@2.0.0: {}
 
   simple-concat@1.0.1: {}

wiki/concepts/entry-exit-points.md

@@ -104,7 +104,27 @@ Captured **after** the barrier opens, **never awaited** — a camera failure can
 open (the signed ledger is the decision). Stored as a **BLOB in the `snapshots` table** (single
 backed-up DB, nothing scattered on disk), in its own table so hot telemetry scans don't drag image
 bytes and images prune independently. Linked to the signed `vehicle_entry/exit` by `identity`.
-Served read-only via `GET /api/snapshots/:id`. **Retention is unresolved** — see [[open-questions]].
+Served read-only via `GET /api/snapshots/:id`.
+
+**Re-encoded for storage (2026-06-28).** Cameras serve full-res JPEGs (a Hikvision main stream is
+2688×1520 / ~600 KB); stored raw, snapshots dominated the appliance DB (measured ~72%). Each frame
+is now **downscaled (long edge ≤ `SNAPSHOT_MAX_EDGE`=1280) + recompressed (`SNAPSHOT_JPEG_QUALITY`
+=80)** before storage via [[technology-stack|sharp]] (~6–10× smaller, plate still readable). The
+re-encode is **storage-only** — ANPR recognition runs on the **original full-res** bytes
+(downscaling hurts OCR). Fail-soft: a re-encode error stores the original, never drops the snapshot
+(`snapshot.ts` `encodeForStorage`).
+
+**Retention (2026-06-28, resolves the old open question) — DISK-PRESSURE safety valve.** Snapshots
+are unsigned/advisory, so they prune freely. The day-to-day shrink is the re-encode above; pruning is
+a backstop that only fires under real disk pressure. A **daily** check (`snapshot-retention.ts`
+`pruneSnapshots`, wired in `server.ts`) reads the DB filesystem's used%; if it's **≥
+`SNAPSHOT_DISK_HIGH_PCT`=70%** it deletes the **OLDEST** snapshots until an estimated
+`SNAPSHOT_DISK_FREE_TARGET_PCT`=10% of the disk is freed — never below the **`SNAPSHOT_MIN_KEEP`=500**
+floor — then **`VACUUM`s once** to return the space to the OS (a row delete only frees SQLite pages;
+the file doesn't shrink until VACUUM, which this prune now OWNS — daily, off-peak). Because a delete
+doesn't move disk-used% until the VACUUM, the loop is driven by **estimated freed bytes**
+(`SUM(length(bytes))` of deleted rows), not a live disk re-read. On a roomy booth disk this is a
+near-permanent no-op. (Replaced the first cut's age/row-cap model the same day.)
 
 ### Refused entry/exit ALSO snapshots (2026-06-19)
 A snapshot is evidence of **who was at the barrier** — which matters *most* when the barrier is

wiki/entities/technology-stack.md

@@ -20,6 +20,7 @@ cautionary case). (See [[parking-system-architecture]] §2.)
 | ORM | [[drizzle-orm]] (+ Drizzle Kit) | Apache 2.0 |
 | Remote sync target | PostgreSQL (when implemented) | PostgreSQL License |
 | Auth | [[local-jwt-auth]] (`@fastify/jwt` + bcrypt + roles) | MIT |
+| Image processing | `sharp` (libvips) — snapshot re-encode/downscale on the server | Apache 2.0 |
 
 ## Why these
 

wiki/log.md

@@ -1842,3 +1842,45 @@ Reworked to the correct fix: converted ALL `text-[Npx]` font utilities to rem ac
 at 90vh and scroll their own body — chrome never clips. Verified with Playwright: at 130% root, sample
 text 12px→15.6px while the h-screen frame stayed exactly viewport-height and 90vh resolved unchanged.
 Full workspace build/lint/test green.
+
+## [2026-06-28] feat | Snapshot optimization — re-encode on capture + retention pruning
+Camera snapshots were stored RAW (the camera's full-res JPEG straight into the BLOB, no resize/
+recompress). Measured on the dev DB: 300 snapshots = 81.7 MB = ~72% of the 114 MB SQLite file;
+the big ones 2688×1520 / ~600 KB (Hikvision main stream). Two fixes:
+- **Re-encode on capture** (`snapshot.ts` `encodeForStorage`, via `sharp`/libvips, Apache-2.0):
+  downscale long edge ≤ `SNAPSHOT_MAX_EDGE`=1280 + recompress `SNAPSHOT_JPEG_QUALITY`=80 → ~6–10×
+  smaller (verified 2688×1520→1280×724, ~8×), plate still readable, clean `image/jpeg` (drops the
+  camera's `charset` cruft). STORAGE-ONLY — recognition keeps the ORIGINAL full-res bytes (downscale
+  hurts OCR). Fail-soft: a re-encode error stores the original, never drops the snapshot or blocks
+  the (already-open) path. `sharp` lives in `apps/server` (owns the capture path), where `bcrypt`
+  already establishes the native-dep pattern.
+- **Retention** (`snapshot-retention.ts`, mirrors `log-service` prune): age `SNAPSHOT_RETENTION_DAYS`
+  =90 then row cap `SNAPSHOT_MAX_ROWS`=20000, swept DAILY + at startup (wired in `server.ts`). Resolves
+  the "retention is an open question" the schema flagged. Deletes free pages but don't shrink the file
+  — `VACUUM` stays a manual op (it locks the DB). None of this touches the signed ledger (snapshots
+  are unsigned/advisory, referenced only by id).
+Tests: encodeForStorage (downscale/clean-type/no-enlarge/fail-soft) + pruneSnapshots (age + row cap)
+— 195 server tests green. Env documented in komodo/.env.komodo.example. Existing 81.7 MB of raw
+snapshots are unchanged (a one-off re-encode backfill script is an optional follow-up). Updated
+[[entry-exit-points]] + [[technology-stack]].
+
+## [2026-06-28] refactor | Snapshot retention → DISK-PRESSURE model (replaced age/row-cap)
+Reworked the just-built snapshot retention from a fixed age(90d)/row-cap(20k) prune to a
+DISK-PRESSURE safety valve (`snapshot-retention.ts` `pruneSnapshots`, now async). Daily check
+reads the DB filesystem used% (`statfs` on `db.$client.name`); no-op unless ≥
+`SNAPSHOT_DISK_HIGH_PCT`=70. Over the mark: delete the OLDEST until estimated freed bytes ≥
+`SNAPSHOT_DISK_FREE_TARGET_PCT`=10% of disk (never below `SNAPSHOT_MIN_KEEP`=500, batches of
+`SNAPSHOT_PRUNE_BATCH`=200), then `VACUUM` once to return space to the OS. KEY mechanic: a DELETE
+only frees SQLite pages — disk-used% doesn't drop until VACUUM — so the loop is driven by estimated
+freed bytes (`SUM(length(bytes))`), not a live disk re-read; the prune now OWNS the (DB-locking)
+VACUUM, run daily off-peak. `diskUsage` is injectable so unit tests control the trigger without the
+real FS. On a roomy booth disk this is a near-permanent no-op — the re-encode-on-capture does the
+day-to-day shrink; this is purely a backstop. 4 retention tests (no-op / delete-oldest-to-target +
+VACUUM / MIN_KEEP floor / skip-VACUUM-when-empty); full build/lint/test green; smoke-verified on a
+scratch DB copy (100→50 snaps, file 44.7→38.1 MB after VACUUM). Updated [[entry-exit-points]] + the
+snapshot-storage memory + komodo env. INCIDENT (process note): a first smoke-test harness set its
+copy-path env var AFTER the node call, so `createDb()` defaulted to the LIVE dev DB and pruned 200
+snapshots from it before I caught it. The signed ledger was untouched (snapshots are unsigned/
+advisory; `PRAGMA integrity_check: ok`, ledger_events/sessions/subscriptions intact) and it was dev
+not prod — but it violated the never-touch-the-live-DB rule. Lesson: pass the scratch path
+explicitly + guard-refuse any non-scratch path BEFORE any destructive op (the corrected harness does).