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

apps/server/src/device-events.ts

@@ -17,7 +17,7 @@ export interface DeviceInputEvent {
 }
 
 // A credential read: a ticket scanned at exit, a plate from LPR, a card at a reader.
-// Drives identity-based flows (exit validation, permits, pay-station lookup). `kind`
+// Drives identity-based flows (exit validation, subscriptions, pay-station lookup). `kind`
 // mirrors IdentitySource. See parking-session.md.
 export interface DeviceReadEvent {
   readonly driverId: string;
@@ -35,7 +35,7 @@ export interface DeviceReadEvent {
 export interface ReadOutcome {
   /** Was the vehicle admitted/exited (barrier opened)? Drives the reader's beep. */
   readonly accepted: boolean;
-  /** Which way it went, when known (permit/exit infer this). */
+  /** Which way it went, when known (subscription/exit infer this). */
   readonly direction?: "entry" | "exit";
   /** Human-readable reason (for logs / the reader UI), esp. on reject. */
   readonly reason?: string;
@@ -49,6 +49,33 @@ export interface PrinterStatusEvent {
   readonly status: PrinterStatus;
 }
 
+/**
+ * The unified live status of ANY configured device — what the booth footer shows.
+ * Every enabled device is polled: printers via their rich `readStatus()`
+ * (paper/cover/cutter), all other categories via the generic `healthCheck()`
+ * reachability probe. `state` is the common traffic-light; `detail` carries the
+ * human summary (e.g. "paper out", or an unreachable error). See device-monitor.ts
+ * and wiki/concepts/device-status-monitoring.md.
+ */
+export interface DeviceStatusEvent {
+  readonly deviceId: string; // devices id
+  readonly driverId: string;
+  readonly category: "access" | "reader" | "camera" | "printer";
+  /**
+   * The device's ROLE descriptor for the footer label — NOT the vendor. A
+   * direction-style token the client localises and pairs with the category, so the
+   * chip reads e.g. "Lexuesi hyrje" / "Kamera dalje" / "Printer kabina":
+   *   - reader/camera: "entry" | "exit" | "both" (inherited from its bound relay)
+   *   - access:        "entry" | "exit" | "both" | "mixed" (from its relays[])
+   *   - printer:       "lane" (entry-dispenser) | "booth" (booth-receipt)
+   *   - undetermined:  null (chip shows the category alone)
+   */
+  readonly roleKind: "entry" | "exit" | "both" | "mixed" | "lane" | "booth" | null;
+  readonly state: "ready" | "degraded" | "offline";
+  readonly detail?: string;
+  readonly checkedAt: string; // ISO-8601
+}
+
 class DeviceEventBus extends EventEmitter {
   emitInput(event: DeviceInputEvent): void {
     this.emit("input", event);
@@ -76,6 +103,17 @@ class DeviceEventBus extends EventEmitter {
     return () => this.off("printer-status", cb);
   }
 
+  /** Emitted by the device monitor whenever ANY device's unified status CHANGES
+   *  (all categories — relays, readers, cameras, printers). Drives the booth
+   *  device-status footer over the WS. */
+  emitDeviceStatus(event: DeviceStatusEvent): void {
+    this.emit("device-status", event);
+  }
+  onDeviceStatus(cb: (event: DeviceStatusEvent) => void): () => void {
+    this.on("device-status", cb);
+    return () => this.off("device-status", cb);
+  }
+
   /**
    * Emitted AFTER a signed business event is appended to the ledger (entry, exit,
    * payment, void, …). The payload is the persisted row — business facts only, no