feat(booth): pay-on-foot at the booth — ticket lookup, pay, exit, voucher, snapshots

Backend: PayStation.lookup (session view + quote in one read); ExitFlow.exitForBooth
reuses the reader path's paid+grace validation (no booth-only unpaid bypass) and
signs vehicle_exit + pulses an exit relay; printExitVoucher reprints the paid ticket
id barcode; site_config.exit_voucher_default (migration 0002) drives the default.
Routes: GET /api/session/:id, POST /api/exit, POST /api/voucher.

Web: BoothPayModal (entry/now/duration/total, tender, 'Printo biletë dalje'),
SnapshotStrip (entry/exit evidence), api.ts client fns, SiteSettings toggle.

packages/db/drizzle/meta/_journal.json

@@ -15,6 +15,13 @@
       "when": 1781682176094,
       "tag": "0001_neat_slipstream",
       "breakpoints": true
+    },
+    {
+      "idx": 2,
+      "version": "6",
+      "when": 1781713560438,
+      "tag": "0002_panoramic_tiger_shark",
+      "breakpoints": true
     }
   ]
 }