feat(offline): tier 2 phase 4 — per-row pending-sync indicators

A small cloud-upload glyph appears next to any row whose id has a
queued offline write (offline-created temp ids and pending edits both
count). Tooltip reads "Pending sync — will save when online". Renders
nothing during normal online operation so the list stays clean.

- DB: `watchPendingIds(domain)` streams the union of target_id and
  temp_id across the queue, scoped per domain.
- Per-domain Riverpod stream providers for notes / tasks / projects.
- New `PendingSyncBadge` widget — used by KnowledgeItemCard (both
  list and grid variants), `_ProjectCard`, and `_TaskRow` in the
  project workspace.

flutter analyze clean; 21 tests pass. Closes #147 — all four phases
of Tier 2 offline mode are in place.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/screens/library/project_tasks_screen.dart

@@ -4,6 +4,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../core/constants.dart';
+import '../../data/local/database.dart';
 import '../../data/models/milestone.dart';
 import '../../data/models/project.dart';
 import '../../data/models/task.dart';
@@ -11,6 +12,7 @@ import '../../providers/api_client_provider.dart';
 import '../../providers/milestones_provider.dart';
 import '../../providers/projects_provider.dart';
 import '../../providers/tasks_provider.dart';
+import '../../widgets/pending_sync_badge.dart';
 
 class ProjectTasksScreen extends ConsumerStatefulWidget {
   final int projectId;
@@ -346,18 +348,28 @@ class _TaskRow extends StatelessWidget {
                 child: Column(
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: [
-                    Text(
-                      task.title.isNotEmpty ? task.title : 'Untitled',
-                      style: theme.textTheme.titleSmall?.copyWith(
-                        decoration: effectiveStatus == TaskStatus.done
-                            ? TextDecoration.lineThrough
-                            : null,
-                        color: effectiveStatus == TaskStatus.done
-                            ? theme.colorScheme.onSurfaceVariant
-                            : null,
-                      ),
-                      maxLines: 2,
-                      overflow: TextOverflow.ellipsis,
+                    Row(
+                      children: [
+                        Flexible(
+                          child: Text(
+                            task.title.isNotEmpty ? task.title : 'Untitled',
+                            style: theme.textTheme.titleSmall?.copyWith(
+                              decoration: effectiveStatus == TaskStatus.done
+                                  ? TextDecoration.lineThrough
+                                  : null,
+                              color: effectiveStatus == TaskStatus.done
+                                  ? theme.colorScheme.onSurfaceVariant
+                                  : null,
+                            ),
+                            maxLines: 2,
+                            overflow: TextOverflow.ellipsis,
+                          ),
+                        ),
+                        PendingSyncBadge(
+                          domain: kSyncDomainTasks,
+                          id: task.id,
+                        ),
+                      ],
                     ),
                     if (task.dueDate != null) ...[
                       const SizedBox(height: 2),

lib/screens/projects/projects_screen.dart

@@ -3,8 +3,10 @@ import 'package:lucide_icons/lucide_icons.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
+import '../../data/local/database.dart';
 import '../../data/models/project.dart';
 import '../../providers/projects_provider.dart';
+import '../../widgets/pending_sync_badge.dart';
 
 class ProjectsScreen extends ConsumerWidget {
   const ProjectsScreen({super.key});
@@ -50,7 +52,12 @@ class _ProjectCard extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return ListTile(
-      title: Text(project.title),
+      title: Row(
+        children: [
+          Flexible(child: Text(project.title)),
+          PendingSyncBadge(domain: kSyncDomainProjects, id: project.id),
+        ],
+      ),
       subtitle: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [