v0.3.0: local free check-in with actionable countdown notification (Phase C)

For a zone labeled free_2h/3h/4h, "Check in (free · Xh)" starts a local, API-free
countdown to the free limit — no ParkSmarter call. The bbp-notify module gains a
showCheckin() that posts the ticking chronometer with "End" / "Pay" buttons, a
BbpActionReceiver (declared in the module's new AndroidManifest.xml) that records
the tap in SharedPreferences and, for Pay, relaunches the app; consumePendingAction()
is drained on foreground by useCheckinSync() — End clears the check-in, Pay hands
off to StartSession for the stored zone. A pre-expiry alert reuses the existing
reminder lead-minutes. Starting a paid session supersedes an active check-in.

Also: MeterDetail shows the free/pay-immediate label and (admins) labeling chips.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/app.json

@@ -3,14 +3,14 @@
     "name": "BigBrainParking",
     "slug": "bigbrainparking",
     "scheme": "bigbrainparking",
-    "version": "0.2.6",
+    "version": "0.3.0",
     "orientation": "portrait",
     "userInterfaceStyle": "automatic",
     "newArchEnabled": true,
     "icon": "./assets/icon.png",
     "android": {
       "package": "top.mowden.bigbrainparking",
-      "versionCode": 16,
+      "versionCode": 17,
       "edgeToEdgeEnabled": true,
       "adaptiveIcon": {
         "foregroundImage": "./assets/adaptive-icon.png",