db: business-layer schema — ledger/device event split, tariffs, permits, sessions

Implements the wiki design in packages/db + packages/shared.

Event split: rename events -> ledger_events (signed business ledger) and add
device_events (unsigned telemetry). ledger_events gains a signed JSON payload
(amount/tariffVersionId/sessionRef/tender…) + keyId; canonicalize() includes
the payload via sorted-key serialization so business data is tamper-evident.
Raw Dingtian input now writes device_events, not a signed input_received.

New tables: tariffs + immutable tariff_versions (composable/versioned, currency
+ FX-ready), permits (+ permit_credentials, permit_plates; maxConcurrent default
1), blocklist, sessions (rebuildable projection cache — not a source of truth).

shared: split ParkingEvent/Type into LedgerEvent/LedgerEventType + DeviceEventKind;
add LedgerPayload, Tender, TariffStructure/TariffBlock.

Regenerated a single baseline migration (no production chain data existed).
Verified: chain appends + verifyChain ok; tampering a payment payload breaks
the signature. Full repo builds (5/5).

apps/server/src/server.ts

@@ -1,7 +1,8 @@
 import cookie from "@fastify/cookie";
 import jwt from "@fastify/jwt";
 import Fastify, { type FastifyInstance } from "fastify";
-import { createDb, type Db } from "@parking/db";
+import { randomUUID } from "node:crypto";
+import { createDb, deviceEvents as deviceEventsTable, type Db } from "@parking/db";
 import { TOKEN_COOKIE, requireJwtSecret } from "./auth.js";
 import { deviceEvents } from "./device-events.js";
 import { EventLog } from "./event-log.js";
@@ -70,39 +71,41 @@ export async function buildServer(opts: BuildOptions = {}): Promise<FastifyInsta
   app.addHook("onReady", async () => printerMonitor.start());
   app.addHook("onClose", async () => printerMonitor.stop());
 
-  // Append-only signed event log. Subscribe device pushes (e.g. Dingtian button
-  // presses) into the hash-chained, signed `events` table — the anti-fraud audit
-  // trail. The device is NOT trusted; the host record is the source of truth, and
-  // a relay open with no matching signed event is itself the anomaly. We record
-  // the raw input faithfully as `input_received` (not yet a `vehicle_entry` — that
-  // comes with the full entry flow). See wiki/concepts/append-only-event-chain.md.
+  // Append-only signed business LEDGER (ledger_events). Holds only business facts
+  // (vehicle_entry/exit, payment, void, …) — the anti-fraud audit trail. A raw
+  // button press is NOT a business fact: it's device telemetry, recorded UNSIGNED
+  // in device_events. The entry flow (TODO) turns an input into a signed
+  // vehicle_entry once a ticket prints + the barrier is commanded.
+  // See wiki/decisions/event-streams-split.md.
   const eventLog = new EventLog(db, buildSigner(app.log));
   await eventRoutes(app, db, eventLog);
   const unsubscribeInput = deviceEvents.onInput((e) => {
     // Resolve which lane the device belongs to. -1 marks "device fired but isn't
     // mapped to a lane" (assigned without a lane, or a stale id) — still recorded
-    // faithfully (the chain is append-only) rather than silently dropped or
-    // mis-stamped as lane 0, which is a real lane.
+    // faithfully rather than silently dropped or mis-stamped as lane 0 (a real lane).
     const lane = laneMap.laneFor(e.deviceId) ?? -1;
     if (lane === -1) {
       app.log.warn(`input from unmapped device ${e.driverId}:${e.deviceId} — logged as lane -1`);
     }
-    eventLog
-      .append({
-        type: "input_received",
-        lane,
-        // `source` is an IdentitySource (wiegand/lpr/qr/ticket/manual) — how a
-        // VEHICLE was identified. A raw input has none, so it stays null. The
-        // device provenance lives in `identity` instead.
-        source: null,
-        identity: `${e.driverId}:${e.deviceId} input:${e.input}/${e.edge}`,
-        occurredAt: e.at,
-      })
-      .catch((err) => app.log.error(`event-log append failed: ${(err as Error).message}`));
+    try {
+      db.insert(deviceEventsTable)
+        .values({
+          id: randomUUID(),
+          deviceId: e.deviceId,
+          lane,
+          category: "access",
+          kind: "input",
+          detail: { driverId: e.driverId, input: e.input, edge: e.edge },
+          occurredAt: e.at,
+        })
+        .run();
+    } catch (err) {
+      app.log.error(`device-event insert failed: ${(err as Error).message}`);
+    }
   });
   app.addHook("onClose", async () => unsubscribeInput());
 
-  // TODO: entry flow (input event → signed event → print → relay).
+  // TODO: entry flow (device input → signed vehicle_entry → print → relay).
 
   return app;
 }