feat(devices): live device-status footer across all categories

Generalise printer-only monitoring to every configured device. New
DeviceMonitor polls all enabled devices each tick (default 8s): printers
via rich readStatus(), relays/readers/cameras via the generic healthCheck()
reachability probe, flattened to one traffic-light (ready/degraded/offline)
+ detail, deduped (emit on change only), fail-toward-offline.

- device-status bus event + GET /api/devices/status snapshot.
- Pushed over the existing /api/ws (hello carries the initial set;
  device-status frame per change).
- Web: live-store devices map, WS handler, DeviceFooter chip-per-device
  (role label not vendor; click a degraded/offline chip for an issues panel).

Verified roleKind resolution + change-only emit on a fresh DB.

Note: the footer's UI surface (api type, router mount, i18n devices) rides
in the subsequent subscription commit due to shared-file overlap.

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

wiki/concepts/booth-console.md

@@ -83,6 +83,15 @@ the Active-Sessions "Open barrier" is disabled the same way. The server enforces
 (`requireShift` 409 `no_shift`) — the UI just front-runs the rejection. The live feed is **scoped to
 the open shift's window** (empty when no shift is open). See [[shift]] for the rule and the routes.
 
+## The device-status footer
+
+A **fixed footer** in the app shell shows the live status of every configured device — relays,
+readers, cameras, printers — one chip each (coloured dot + name + fault detail), with an "all ready
+/ N offline" roll-up. Fed by the unified [[device-status-monitoring|DeviceMonitor]] over the same
+`/api/ws` socket (`hello` carries the initial set; a `device-status` frame per change), held in the
+live store keyed by device id, with `GET /api/devices/status` as the seed/fallback. Visible on every
+screen, so the operator always sees the barrier relay's reachability and the printer's paper state.
+
 ## Dev notes
 - Vite proxies `/api/ws` (`ws: true`) to the backend; the backend's Origin allowlist must include the
   dev SPA origin (`WS_ALLOWED_ORIGINS=http://localhost:5173`). In production Fastify serves the SPA

wiki/concepts/device-status-monitoring.md

@@ -0,0 +1,100 @@
+---
+type: concept
+tags: [parking, device, monitoring, reliability, ui]
+sources: []
+updated: 2026-06-18
+status: open
+---
+
+# Device status monitoring (the booth footer)
+
+The booth shows a **fixed footer** with the live status of every configured device — relays,
+readers, cameras, printers — so an operator sees at a glance that the barrier relay is reachable,
+the exit scanner is up, and the ticket printer has paper. This generalises the printer-only
+[[printer-status-monitoring]] to **all four [[device-adapter-pattern|device categories]]**. A
+reliability control, not a threat-model one. (Built 2026-06-18.)
+
+## What gets polled, and how
+
+Every **enabled** row in `devices` is polled on an interval, regardless of category — the monitor
+talks only to the adapter interfaces ([[device-adapter-pattern]]), never a driver SDK:
+
+- **Printers** → their rich `MonitorableDevice.readStatus()` (paper end / near-end, cover open,
+  cutter error, off-line) — the same capability the existing [[printer-status-monitoring|PrinterMonitor]]
+  uses. The footer surfaces the fault detail.
+- **Relays / readers / cameras** → the generic `Device.healthCheck()` **reachability** probe every
+  adapter implements (`ready | degraded | offline`). This is presence/up-ness, not a deep fault
+  model — a relay either answers or it doesn't.
+
+Both collapse to one **traffic-light**: `ready | degraded | offline`, plus a `detail` string. Fail
+**toward "there's a problem"**, never false-healthy: a probe that throws or times out reads
+`offline` (consistent with [[printer-status-monitoring]]'s fail-safe mapping); a driver that's no
+longer registered reads `offline` ("driver not registered") rather than vanishing.
+
+## The monitor (server)
+
+`DeviceMonitor` (`apps/server/src/device-monitor.ts`), modelled on the PrinterMonitor:
+
+- re-reads the device set each tick (a newly-assigned/removed device appears/disappears without a
+  restart); drops cached status for devices that are gone or disabled;
+- polls every `DEVICE_POLL_MS` (default **8000ms**), never overlapping ticks;
+- caches the latest unified status per device id;
+- emits a `device-status` bus event **only when a device's state or detail changes** (deduped).
+
+> **Relationship to the PrinterMonitor.** Both run. The PrinterMonitor stays the authority for the
+> printer-specific live detail + its SSE stream (`/api/printers/status*`) that the entry flow may
+> later depend on for [[printer-roles-failover]]. The DeviceMonitor is the **unified footer feed**
+> across all categories. They poll independently (printers get probed by both — cheap HTTP reads);
+> the small duplication is deliberate, to avoid coupling the footer to printer internals. Could be
+> consolidated later if the overlap ever matters.
+
+## API / live UI
+
+- `GET /api/devices/status` — cached snapshot of all devices (no device round-trip). Any
+  authenticated role (operational, not a setup action).
+- Live updates ride the **one booth [[booth-console|WebSocket]]** (`/api/ws`): the `hello` frame
+  carries the initial device-status set; a `device-status` frame is pushed per change. The web
+  [[booth-console|live store]] holds the set keyed by device id; the REST snapshot seeds it / fills
+  in if the socket is briefly down.
+- **`DeviceFooter`** (`apps/web/src/ui/DeviceFooter.tsx`) renders one **compact** chip per device —
+  a coloured dot + a **role label, never the vendor** — ordered access → reader → camera → printer,
+  with a right-aligned roll-up ("N with issues" / "all ready"). Mounted in the app shell so it's
+  visible on every screen.
+
+### Label = role, not vendor (refinement 2026-06-18)
+
+The chip shows **what the device does, not who made it**: the localised category + a role/direction
+suffix → `Lexuesi hyrje`, `Printer kabina`, `Kamera dalje`. The server sends a structured
+**`roleKind`** token (not a composed string), the client localises it:
+- **reader / camera** → the direction inherited from its bound relay (`directionOf()` in
+  [[entry-exit-points|device-resolve]]): `entry | exit | both`.
+- **access controller** → `entry | exit | both` from its `relays[]`, or **`mixed`** when it spans
+  more than one direction; `null` if it declares none yet.
+- **printer** → `lane` (entry-dispenser) | `booth` (booth-receipt) — the [[printer-roles-failover]] role.
+- `null` → the chip shows the category alone.
+
+### Detail does NOT pollute the footer (refinement 2026-06-18)
+
+Chips stay short — **no inline fault text**. A device that is `degraded`/`offline` is clickable (so
+is the roll-up); clicking opens a small **issues panel** anchored above the footer that lists only
+the problem devices with their role label, state, the `detail` string, and the last-checked time.
+`ready` chips are non-interactive. The panel closes on outside-click / Escape (a lightweight
+popover — no extra dependency; only Radix Dialog is installed).
+
+## Verified (2026-06-18)
+
+On a fresh DB seeded with a stub relay, a TCP reader, and two printers (one reachable, one not):
+relay + reader → `ready` via `healthCheck`; the unreachable printer → `offline` (with a detail
+string, never threw); the bus emitted once per device on first observation, and a second unchanged
+tick was silent (change-only emit). Server + web build clean.
+
+## Open / not yet done
+
+- **Reachability ≠ correctness.** `healthCheck()` says a relay/reader answers, not that it's wired
+  to the right barrier or reading cards — that's a setup/precondition concern ([[first-run-setup]],
+  the Dingtian [[access-controller-button-flow|precondition checks]]).
+- **No per-device history / alerting.** The footer is point-in-time; a flapping device isn't
+  tracked over time. Reconciliation-style alerting is out of scope here.
+- **Cameras** only expose `healthCheck` reachability today; a "last snapshot age" health signal
+  could be richer ([[lpr-camera]], [[opencv-anpr-service]]).
+- Possible later **consolidation** of PrinterMonitor + DeviceMonitor (see the note above).

wiki/concepts/printer-status-monitoring.md

@@ -7,6 +7,11 @@ updated: 2026-06-14
 
 # Printer status monitoring
 
+> **Generalised 2026-06-18:** the booth's all-device status **footer** is a separate, unified
+> monitor across every category (relays/readers/cameras/printers) — see
+> [[device-status-monitoring]]. This page remains the authority for the *printer-specific* rich
+> status (paper/cover/cutter) + its SSE stream; both monitors run.
+
 The booth must know a printer is in trouble **before** a driver presses the entry button and no
 ticket comes out. So the system polls each printer's live status (paper out, cover open, cutter
 jam, off-line) and pushes changes to the operator UI. A reliability control, like