Replace the customer app with Doormile CX

Book a pickup, track it to delivery — the rebuilt customer app.

- Design language from doormile-screens.html: brand #8F0F06, Manrope +
  Geist Mono (variable fonts), bordered cards instead of shadows, crimson
  brand headers, sliding tab indicator, mono for anything read digit by digit.
- lib/data (one live API implementation, plus a debug-only offline fake),
  lib/state, lib/ui (tokens, widgets, screens).
- 84 tests, plus a design snapshot harness that renders every screen with the
  real fonts: flutter test test/design_snapshot_test.dart --run-skipped
  --update-goldens

This replaces the previous app (pubspec 'doormile', app id
com.doormile.customer). That tree remains in history at 6c7d656; note its
android/app/google-services.json is not carried over, and the application id
here is in.doormile.customer.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

lib/ui/format.dart

@@ -0,0 +1,80 @@
+/// Small formatting helpers shared across screens.
+library;
+
+String greetingForNow([DateTime? now]) {
+  final h = (now ?? DateTime.now()).hour;
+  if (h < 12) return 'Good morning';
+  if (h < 17) return 'Good afternoon';
+  return 'Good evening';
+}
+
+/// "Just now" / "18 min ago" / "3 hr ago" / "5 d ago"
+String relativeTime(DateTime? at, [DateTime? now]) {
+  if (at == null) return '';
+  final mins = (now ?? DateTime.now()).difference(at).inMinutes;
+  if (mins < 1) return 'Just now';
+  if (mins < 60) return '$mins min ago';
+  final hrs = (mins / 60).round();
+  if (hrs < 24) return '$hrs hr ago';
+  return '${(hrs / 24).round()} d ago';
+}
+
+const _months = [
+  'Jan',
+  'Feb',
+  'Mar',
+  'Apr',
+  'May',
+  'Jun',
+  'Jul',
+  'Aug',
+  'Sep',
+  'Oct',
+  'Nov',
+  'Dec',
+];
+
+/// "Today" / "Yesterday" / "29 Aug"
+String dateLabel(DateTime date, [DateTime? now]) {
+  final today = now ?? DateTime.now();
+  bool sameDay(DateTime a, DateTime b) =>
+      a.year == b.year && a.month == b.month && a.day == b.day;
+
+  if (sameDay(date, today)) return 'Today';
+  final yesterday = today.subtract(const Duration(days: 1));
+  if (sameDay(date, yesterday)) return 'Yesterday';
+  return '${date.day} ${_months[date.month - 1]}';
+}
+
+/// "SEPTEMBER 2026" — the eyebrow over a tab root's title. Spelled in full
+/// rather than abbreviated: it is read once, at the top of the screen, and
+/// "SEP 2026" saves four characters nobody needed saved.
+String monthLabel(DateTime date) => '${_monthsFull[date.month - 1]} ${date.year}';
+
+const _monthsFull = [
+  'January',
+  'February',
+  'March',
+  'April',
+  'May',
+  'June',
+  'July',
+  'August',
+  'September',
+  'October',
+  'November',
+  'December',
+];
+
+/// Initials for an avatar, e.g. "Joe Oommen" -> "JO".
+String initialsOf(String? name) {
+  final n = (name ?? '').trim();
+  if (n.isEmpty) return 'DM';
+  final letters = n
+      .split(RegExp(r'\s+'))
+      .map((p) => p.isEmpty ? '' : p[0])
+      .join();
+  return letters
+      .substring(0, letters.length < 2 ? letters.length : 2)
+      .toUpperCase();
+}