UI Phase 2 (L0): shared layout primitives + chrome standardization

Extract four shared layout widgets from the best existing implementations and
adopt them across list/overview screens, deleting duplicated inline code.
Layout/consistency only — no behavior change.

New primitives (lib/widgets/):
- app_section_header.dart  — AppSectionHeader (azure accent bar + uppercase
  telemetry label; promoted from the dashboard's _sectionTitle).
- app_metric_card.dart     — AppMetricCard (uppercase label + mono value on a
  flat hairline surface; unifies KPI/stat tiles).
- app_status_summary.dart  — AppStatusSummaryRow/Item/Chip (dot + count + label,
  selectable; semantic AppStatusColors).
- app_filter_bar.dart      — AppFilterBar (responsive filter-row chrome).

Adopted / de-duplicated:
- Dashboard: _MetricCard now wraps AppMetricCard; section titles use
  AppSectionHeader (removed local _sectionTitle).
- Tickets / Tasks / ISR: three separate summary-chip implementations
  (_StatusSummaryCard x2, _SummaryChip) collapsed into AppStatusSummaryRow.
- Network Map overview: Sites/Devices tiles -> AppMetricCard (removed local
  _SummaryCard).
- Workforce: "Duty Schedules" header -> AppSectionHeader with trailing chip.

Verified: flutter analyze lib clean; flutter build web green; visual QA (tickets
+ ISR summary chips) in dark.

Co-Authored-By: claude-flow <ruv@ruv.net>

lib/screens/workforce/workforce_screen.dart

@@ -16,6 +16,7 @@ import '../../providers/chat_provider.dart';
 import '../../providers/ramadan_provider.dart';
 import '../../providers/notifications_provider.dart';
 import '../../widgets/app_page_header.dart';
+import '../../widgets/app_section_header.dart';
 import '../../widgets/app_state_view.dart';
 import '../../widgets/responsive_body.dart';
 import '../../theme/app_surfaces.dart';
@@ -126,22 +127,15 @@ class _SchedulePanel extends ConsumerWidget {
       children: [
         Padding(
           padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
-          child: Row(
-            children: [
-              Text(
-                'Duty Schedules',
-                style: Theme.of(
-                  context,
-                ).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w700),
-              ),
-              const Spacer(),
-              FilterChip(
-                label: const Text('Show past'),
-                selected: showPast,
-                onSelected: (v) =>
-                    ref.read(showPastSchedulesProvider.notifier).state = v,
-              ),
-            ],
+          child: AppSectionHeader(
+            'Duty Schedules',
+            padding: EdgeInsets.zero,
+            trailing: FilterChip(
+              label: const Text('Show past'),
+              selected: showPast,
+              onSelected: (v) =>
+                  ref.read(showPastSchedulesProvider.notifier).state = v,
+            ),
           ),
         ),
         const SizedBox(height: 4),