v0.6.1: stop Anonymous Mode bouncing to sign-in on every foreground

Parking without an account showed "Your session expired — please sign in
again." repeatedly and kicked the user back to the login screen.

The 401 hook on the API client is global: it fires on every unauthorized
response whether or not the caller caught the error. Anonymous Mode has no
token, so any ParkSmarter call 401s, and two of them run automatically —
discoverPaidSession() on open and every foreground, and the map's
lastSessionLot() on every mount. Each one flipped the status to signedOut;
re-entering anonymous mode ran them again, hence "over and over".

Both call sites already caught their errors, which is why this hid: the
bounce came from the client hook, not from the catch.

- A 401 in Anonymous Mode is no longer treated as a session expiry. There is
  no session to expire, and bouncing to sign-in makes the mode pointless.
  This also covers the Sessions/Favorites/Scan tabs, which 401 the same way.
- authBus carries the mode to the non-React modules that need it.
- discoverPaidSession() and lastSessionLot() are skipped entirely when
  anonymous rather than fired and discarded.
- "Last lot" now says it needs an account instead of silently doing nothing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/app.json

@@ -3,14 +3,14 @@
     "name": "BigBrainParking",
     "slug": "bigbrainparking",
     "scheme": "bigbrainparking",
-    "version": "0.6.0",
+    "version": "0.6.1",
     "orientation": "portrait",
     "userInterfaceStyle": "automatic",
     "newArchEnabled": true,
     "icon": "./assets/icon.png",
     "android": {
       "package": "top.mowden.bigbrainparking",
-      "versionCode": 21,
+      "versionCode": 22,
       "edgeToEdgeEnabled": true,
       "adaptiveIcon": {
         "foregroundImage": "./assets/adaptive-icon.png",