feat(booth): refusal snapshots, subscriber access medium, one-car-one-ticket entry

Three booth-integrity improvements that share the entry/exit flows and activity log.

Refusal snapshots: previously only an accepted open captured a camera image; now
every refusal/hold anomaly fires the directional camera too (a turned-away car is
exactly the evidence wanted) — entry refused-full/held, exit refused
closed/no-session/unpaid/grace-expired (booth + reader paths), refused subscription.
A refused entry has no ticket id, so a synthetic REFUSED- ref keys the anomaly + photo
together. Same fire-and-forget contract; failed captures still show as tiles.

Subscriber access medium: the subscription flow already signed `via`
(qr|card|plate) into entry/exit payloads; surface it as a typed LedgerPayload.via, a
cyan chip in the ticker, and an "Entry medium" modal row (sq+en). Display-only.

One car = one ticket: the entry button could be mashed to mint many tickets per car
(corrupting occupancy + enabling ticket-shopping at exit) — the old #inFlight guard
only blocked overlapping presses. Add a per-relay guard configured on the relay spec:
PRESENCE mode (presenceInput ties ticketing to a vehicle loop on a Dingtian input —
one ticket per car, re-armed when the loop clears) or COOLDOWN fallback
(entryCooldownSec) when there's no barrier feedback. A suppressed press is unsigned
device_events telemetry, not a signed anomaly. SetupWizard exposes both fields.
Fail-closed entry and barrier-is-not-a-door invariants untouched; guard state is
in-memory/rebuildable, starts armed after restart.

Wiki: new entry-double-press; updated entry-exit-points, booth-console, index.

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

packages/shared/src/index.ts

@@ -152,6 +152,11 @@ export interface LedgerPayload {
   /** Interpolation values for `reasonCode`'s message template (counts, ids, ratios).
    *  Signed alongside the code so the rendered sentence is reproducible. */
   readonly reasonParams?: Record<string, string | number>;
+  /** subscription entry/exit: which credential the subscriber presented — `"qr"`
+   *  (QR code), `"card"` (RFID/NFC card or chip), or `"plate"` (bound plate / LPR).
+   *  Signed so the activity log can show HOW a subscriber entered/left (e.g. "via QR"),
+   *  and so a lost-card investigation can trace which credential was used. */
+  readonly via?: "card" | "qr" | "plate";
   /** plate/vehicle from the vision service (advisory). */
   readonly plate?: string;
   readonly plateConfidence?: number;