Session expiry, arrival geofence guard, multi-destination stops

Three fixes found by running the app on a real handset against production.

1. An expired token left the app looking signed in and unable to work.
   MilerApi.onUnauthorized was declared and called on every 401 but never
   assigned, so the token was dropped and nothing else happened: the profile
   stayed on disk, logged_out stayed false, and the rider saw his own name over
   a dashboard whose every call returned 401. He reads that as "no work today".
   The teardown now lives in endSession() and both ways out of a session — the
   Log out button and the 401 path — use it.

2. Arrived was written locally even when the rider was not there.
   updateArrivedStatus answers false for three different things and the caller
   treated all of them as "the write did not land", which is only true of one.
   A geofence refusal and a server refusal now stop the rung and hand back the
   reason; a dead network still advances, as it should.

3. A multi-destination customer pickup collapsed onto one stop.
   GET /miler/bookings returns a row per destination once collected, all with
   the same bookingid and reference. Every local store keys on that id, so the
   accepted store deduped two of three drops away and their consignment ids
   were unrecoverable. orderid is now the stop key; bookingreference stays the
   booking's name. Cards show "Stop 2 of 3" and the receiver's own name and
   number rather than the sender's.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EqVJPB9B4QuieZnBAAKgYQ

test/deliver_identity_test.dart

@@ -56,22 +56,35 @@ void main() {
       );
     });
 
-    test('the mapping is per rider and per line', () async {
+    test('the mapping is per rider — and follows him across lines', () async {
+      // ── This asserted the opposite until 2026-09-16 ──
+      //
+      // The scope key carried a third part, the rider's service line:
+      // `consignment_ids::u38.t13.milkMan`. That was right while a rider was
+      // one thing for the life of his account. He is not — one Miler carries
+      // meal parcels, logistics collections and customer pickups in the same
+      // shift — and keying his records by a line split one day's work across
+      // two drawers, with whichever drawer the app resolved into being the only
+      // one he could see.
+      //
+      // For a *consignment id* that was not a cosmetic loss: the id is what
+      // `deliver` and `skip` key on, so a stop collected while the app read one
+      // line and delivered after it read the other could not be closed at all.
+      // The rider was told "this order was never picked up on the system".
       await rememberConsignmentId('ORDER-1', '46');
 
       ServiceProfile.setActive(ServiceProfile.parcel);
       expect(
         (await getConsignmentIds())['ORDER-1'],
-        isNull,
-        reason: "one line's consignment mapping is not another's",
+        '46',
+        reason: 'one rider, one day, one drawer — whatever he is carrying',
       );
 
       SharedPreferences.setMockInitialValues({'userid': 99});
-      ServiceProfile.setActive(ServiceProfile.milkMan);
       expect(
         (await getConsignmentIds())['ORDER-1'],
         isNull,
-        reason: "another rider's handset drawer is not this one",
+        reason: "another rider's handset drawer is still not this one",
       );
     });