Miler rider app: surface system, visible design language, backend lifecycle

Design system
- MilerSurface ladder (canvas → working → raised → floating) with MilerPanel
  as layer 1; canvas moved to #DEE3EA so white separates at 1.290:1.
- Visible vocabulary applied across Home, Deliveries, Activity, Account and
  the sheets: hero heads (tabular numeral + small caption, clamped at 1.3x),
  canvas wells for anything that opens, small filled tags for shelf labels,
  demoted placeholders. Recorded in DESIGN_SYSTEM.md §6.
- One icon family: 222 Material glyphs migrated to Lucide; none left outside
  lib/xpress.
- Colour semantics corrected: amber only for what is genuinely owed, brand red
  reserved for the live stop, disabled primaries go neutral rather than pale.

Data and lifecycle
- lib/data/lifecycle.dart reads mutations for what they prove; route_order.dart
  makes admin sequence the single ordering authority; service_day.dart, and
  stop_area.dart rewritten against live Coimbatore addresses (digit-token
  stripping, city stoplist, street suffixes, stammer collapse).
- countLabel states the load once, in bags.

Testing
- 1440 tests passing; golden shot harnesses for Home, Deliveries, Activity,
  sheets and verify, with test/failures/ now gitignored (diff debris).
- New pins: home_gutter_test, stop_area_test, plus updated structural bounds.

Note: this commit also carries pre-existing working-tree deletions that were
present before this work (API_SPEC.md, README.md, demo test fixtures).

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

lib/utils/external_navigation.dart

@@ -0,0 +1,34 @@
+import 'package:flutter/foundation.dart';
+import 'package:url_launcher/url_launcher.dart';
+
+/// Hands a destination to the phone's own maps app.
+///
+/// Native intent first, web as the fallback, so a rider gets the same app
+/// whichever control in Miler he presses. Three screens had their own copy of
+/// these two URLs — a route row, a map screen and a confirmation sheet — which
+/// is three chances for one of them to open a different app, or the wrong
+/// scheme, on the one action a rider takes at every single stop.
+///
+/// Silent on failure by design: there is nothing useful to say to a rider whose
+/// phone has no maps application, and the screen he pressed from still has the
+/// address on it.
+Future<void> openExternalNavigation(double lat, double lng) async {
+  try {
+    final native = Uri.parse('google.navigation:q=$lat,$lng&mode=d');
+    if (await launchUrl(native, mode: LaunchMode.externalApplication)) return;
+  } catch (_) {
+    // Falls through to the web URL below — a device with no navigation intent
+    // handler is the normal case on iOS, not an error.
+  }
+  try {
+    await launchUrl(
+      Uri.parse(
+        'https://www.google.com/maps/dir/?api=1'
+        '&destination=$lat,$lng&travelmode=driving',
+      ),
+      mode: LaunchMode.externalApplication,
+    );
+  } catch (e) {
+    debugPrint('[NAV] could not open maps: $e');
+  }
+}