docs(camera): lane presence + ANPR subscriber-entry bridge design

Captures this session's back-and-forth as a new concept page
[[lane-presence-and-anpr-entry]] and cross-links it:

- BUILT: advisory lane busy/free booth lights (LaneStatus + WS), with the
  measured camera limits behind the 30s timeout (no leave signal; movement-
  driven re-fire; notificationRecurrence locked to "beginning" — ISAPI flip
  silently reverts).
- PLANNED: the ANPR "bridge" — explicitly a small apps/server HANDLER (~40
  lines), NOT a new service/container. On a camera vehicle event: snapshot ->
  ANPR -> high-confidence match -> debounce -> emitRead{kind:"plate"}, then
  the existing subscription match/dispatch/gate admits the subscriber. Both
  directions, opt-in (config.anpr), plate never the sole authority.
- Records the decisions (high confidence floor, debounce-for-correctness)
  and the REJECTED ideas (continuous livestream / per-car queue tracking /
  make-model) with why, plus the open hardware question (booth-PC test).

Updates subscription.md (plate matching is built; the live source is this
bridge) and lpr-camera.md (the two consumers of the vehicle event).

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

wiki/entities/lpr-camera.md

@@ -82,10 +82,12 @@ Center**, then **Alarm Settings → Alarm Server**, makes the camera **HTTP-POST
   sends** (inspect via `GET /api/events` or the server log) before wiring it to the read bus.
 - **Not yet a barrier trigger.** It records + breadcrumbs only; it does NOT emit a `DeviceReadEvent`
   or open anything. A plate read is **advisory, never the sole reason** a barrier opens
-  ([[append-only-event-chain]], [[opencv-anpr-service]]) — the entry/exit wiring is a deliberate
-  next step once the real payload is known. If the camera emits its own plate (`<plateNumber>`), we
-  can use it as an advisory read directly; otherwise the server hands the attached/pulled frame to
-  the [[opencv-anpr-service|vision service]] for ANPR.
+  ([[append-only-event-chain]], [[opencv-anpr-service]]). Two consumers were since designed off this
+  same vehicle event — see **[[lane-presence-and-anpr-entry]]**: (a) BUILT — advisory lane busy/free
+  booth lights; (b) PLANNED — the ANPR "bridge" that snapshots → ANPR → emits a `kind:"plate"` read
+  for a SUBSCRIBER match through the existing gated flow (a small `apps/server` handler, not a
+  service). If the camera ever emits its own `<plateNumber>` we'd use it directly; this `DS-2CD1043G2`
+  does not, so the server pulls the frame and hands it to the [[opencv-anpr-service|vision service]].
 
 ### Gotchas learned the hard way (2026-06-22 field session)