Remove UHPPOTE/ZKTeco; Dingtian is the only access driver

Neither UHPPOTE nor ZKTeco is used — the Dingtian relay controller was chosen
and verified. Remove their code and re-scope the wiki.

Code:
- delete access-uhppote.ts, uhppoted.d.ts, access.ts (zkteco/esp32-relay stubs),
  and the three uhppote-*.mjs hardware test scripts.
- remove the `uhppoted` npm dependency from @parking/devices and @parking/server.
- unregister uhppote/zkteco/esp32-relay from the driver registry; drop their
  exports. Catalog access drivers = dingtian only. Build green (5/5).
- refresh now-stale example comments (registry/interfaces/setup/api) to use
  current examples; keep the two "UHPPOTE blocker" references that explain why
  the precondition capability exists.

Wiki (kept pages, re-scoped):
- uhppote-controller, zkteco-controller -> rejected/historical with callouts;
  uhppote-vs-esp32 -> historical (detection-vs-prevention lens still useful).
- re-point all "current device" framing (standing-decisions, bom, overview,
  open-questions, device-registry, device-discovery, index) to dingtian-relay.
- transferable concepts (network-isolation, event-log-ingestion, barrier-not-a-
  door, threat-model) untouched. Raw source immutable. Links lint clean.

packages/devices/src/interfaces.ts

@@ -14,7 +14,7 @@ export type DeviceCategory = "access" | "reader" | "camera" | "printer";
 
 /** Lifecycle shared by every device adapter. */
 export interface Device {
-  /** Stable id of the driver that produced this instance (e.g. "zkteco"). */
+  /** Stable id of the driver that produced this instance (e.g. "dingtian"). */
   readonly driverId: string;
   connect(): Promise<void>;
   disconnect(): Promise<void>;
@@ -28,7 +28,7 @@ export interface DeviceHealth {
 }
 
 // --- Access control (barrier relay) --------------------------------------
-// ZKTeco, an ESP32 relay controller, UHPPOTE, etc. all implement this.
+// The Dingtian relay board (and any future relay controller) implements this.
 export interface AccessControlDevice extends Device {
   /** Express intent to open. NEVER timed/forced closed against a vehicle. */
   pulseOpen(doorId: number): Promise<void>;