feat(entry): admin bypass of the presence gate for faulty radar/camera

The entry button (physical press AND the operator-issued mint) requires
radar/loop presence + camera detection to confirm a real vehicle. When one
of those devices is faulty, the gate blocks legitimate transient entry. Let
the ADMIN drop a specific signal as a requirement until support fixes the
hardware — the admin is not the adversary, but weakening an anti-fraud gate
stays attributed and auditable:

- Granular: bypass radar and camera independently (Setup → controller
  section). A dead camera drops only the camera check; a dead radar only
  radar. Both off = normal gate; both on = press-to-print.
- Signed: a DEDICATED endpoint (PUT /api/site-config/presence-bypass,
  site:update) appends a signed config_change {setting, value, prev,
  operator} per actually-changed signal — new ledger type. No-op toggles
  sign nothing; disabling signs too. Kept out of the generic site PUT.
- Flagged: every vehicle_entry issued (and every refusal anomaly) while
  bypassed carries presenceBypassed:[...] in its signed payload.
- Persists until turned off; amber warning in Setup while active. The
  booth entry light treats a bypassed signal as satisfied (server
  re-checks authoritatively). Physical-button path falls through to the
  cooldown backstop when radar is bypassed.
- Migration 0020: two boolean site_config columns (default off).

Fixes a latent bug surfaced by the tests: firstRelayByDirection returned no
presenceInput, so issueForOperator's radar gate always read "presence loop
unavailable" — operator-issue never actually gated on radar. The resolver
now attaches the presence input serving the relay (mirrors relayForButton).

10 new tests: 5 gate combinations (each bypass drops only its signal +
records it), 5 route tests (RBAC, signed transitions, no-op, validation).

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

packages/db/src/schema.ts

@@ -251,6 +251,20 @@ export const siteConfig = sqliteTable("site_config", {
   anprEntryEnabled: integer("anpr_entry_enabled", { mode: "boolean" })
     .notNull()
     .default(true),
+  /** Entry presence-gate BYPASS (2026-07-02). The entry button — physical press and the
+   *  operator-issued mint — requires a real vehicle at the barrier: radar/loop presence AND
+   *  camera detection. When a device is FAULTY, the admin can drop one of those signals as a
+   *  requirement until support fixes it (the admin is not the adversary). Granular: a dead
+   *  camera → set bypassPresenceCamera (radar still gates); a dead radar → bypassPresenceRadar.
+   *  Both false (default) = the normal both-required gate; both true = press-to-print with no
+   *  presence check. Enabling/disabling is signed as a `config_change` and every ticket issued
+   *  while bypassed is flagged. Stored 0/1. See wiki/concepts/entry-presence-bypass.md. */
+  bypassPresenceRadar: integer("bypass_presence_radar", { mode: "boolean" })
+    .notNull()
+    .default(false),
+  bypassPresenceCamera: integer("bypass_presence_camera", { mode: "boolean" })
+    .notNull()
+    .default(false),
   /** IANA timezone the site operates in (e.g. "Europe/Tirane"). Used to evaluate a
    *  tariff's wall-clock pricing windows (happy hour / night / seasonal). COPIED into
    *  each published tariff version's structure.tz so the windows are frozen/immutable