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.

wiki/overview.md

@@ -29,11 +29,12 @@ deployed on-site at a parking facility. Two forces shape nearly every decision:
   rest ([[disk-os-hardening]]) defends a secondary threat.
 - **Devices** sit behind a [[device-adapter-pattern]] (swap hardware → new adapter only), with
   the [[barrier-not-a-door]] safety principle keeping physical safety in barrier-operator firmware.
-- **Access control** hinges on the [[trust-boundary]] fork:
-  [[uhppote-vs-esp32|detection vs. prevention]]. Today: [[uhppote-controller]] behind
-  [[network-isolation]], its open [[uhppote-udp-protocol]] contained, its log made trustworthy by
-  [[event-log-ingestion]]. Upgrade path: the [[esp32-custom-controller]] with
-  [[challenge-response-auth]] and [[fail-state-safety]].
+- **Access control** today is the **[[dingtian-relay]]** relay+input controller behind
+  [[network-isolation]] — chosen because its inputs are **decoupled from its relays**, enabling
+  host-in-the-loop ticket-first entry (resolving [[access-controller-button-flow]]). The
+  [[uhppote-controller]] and [[zkteco-controller]] were evaluated and **rejected** (historical).
+  The deeper fork is still the [[trust-boundary]] ([[uhppote-vs-esp32|detection vs. prevention]]);
+  the [[esp32-custom-controller]] remains the prevention-grade alternative.
 - **Readers** split two ways ([[entry-exit-readers]]): permit holders via [[wiegand]]
   (autonomous), casual/transient via host-side [[lpr-camera]] / QR; both can share a relay.
 - A reference [[bom]] lists recommended devices.
@@ -47,6 +48,6 @@ modes (fail-open on exit)**, the **reconciliation channel**, and **backup/durabi
 
 - *Security-first:* [[threat-model]] → [[append-only-event-chain]] → [[reconciliation]] →
   [[uhppote-vs-esp32]].
-- *Hardware-first:* [[bom]] → [[uhppote-controller]] → [[entry-exit-readers]] →
-  [[esp32-custom-controller]].
+- *Hardware-first:* [[bom]] → [[dingtian-relay]] → [[access-controller-button-flow]] →
+  [[entry-exit-readers]].
 - *Stack-first:* [[technology-stack]] → [[offline-first]] → [[device-adapter-pattern]].