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.

apps/web/src/api.ts

@@ -110,7 +110,7 @@ export interface DiscoveredDevice {
   health: { status: string; detail?: string };
 }
 
-/** Scan the LAN for devices a driver can discover (e.g. UHPPOTE). Admin-only. */
+/** Scan the LAN for devices a driver can discover. Admin-only. */
 export async function discoverDevices(driverId: string): Promise<DiscoveredDevice[]> {
   const body = await apiFetch<{ devices: DiscoveredDevice[] }>(
     `/api/setup/discover/${driverId}`,