milestone 5: tag chips, edit-before-sync, share target, last synced, sync interval

- CaptureScreen: FlowRow of FilterChip from recent tags; tap to toggle tag in/out
- CaptureViewModel: recentTags flow (flat deduplicated from last 100 captures), lastSyncedAt, toggleTag()
- HistoryScreen: tap to expand rows, edit dialog for pending/failed, last synced in TopAppBar subtitle
- HistoryViewModel: lastSyncedAt flow, updateBody()
- CaptureDao: getLastSyncedAt(), getRecentTagsJson() (from prior commit), updateBody()
- SettingsScreen: sync interval field (number, min 15), SynqSettings.syncIntervalMinutes
- SettingsViewModel: reschedules WorkManager on save with new interval
- SyncWorker: schedule() takes intervalMinutes param, uses REPLACE policy
- AndroidManifest: ACTION_SEND text/plain intent-filter on MainActivity
- MainActivity: extracts EXTRA_TEXT on share, passes as URL-encoded nav arg to CaptureScreen

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

android/app/src/main/AndroidManifest.xml

@@ -19,6 +19,11 @@
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/plain" />
+            </intent-filter>
         </activity>
 
     </application>