feat: add local-first private AI digest workflow

Migrate app code into canonical feature slices, add phone-only AI digest scheduling and review, wire local notification/background task support, and cover the flow with tests.

android/app/src/main/AndroidManifest.xml

@@ -1,4 +1,5 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
     <application
         android:label="relationship_saver"
         android:name="${applicationName}"
@@ -6,7 +7,7 @@
         <activity
             android:name=".MainActivity"
             android:exported="true"
-            android:launchMode="singleTop"
+            android:launchMode="singleTask"
             android:taskAffinity=""
             android:theme="@style/LaunchTheme"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
@@ -24,12 +25,31 @@
                 <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/*"/>
+            </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.SEND_MULTIPLE"/>
+                <category android:name="android.intent.category.DEFAULT"/>
+                <data android:mimeType="text/*"/>
+            </intent-filter>
         </activity>
         <!-- Don't delete the meta-data below.
              This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
         <meta-data
             android:name="flutterEmbedding"
             android:value="2" />
+        <receiver android:exported="false" android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationReceiver" />
+        <receiver android:exported="false" android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver">
+            <intent-filter>
+                <action android:name="android.intent.action.BOOT_COMPLETED"/>
+                <action android:name="android.intent.action.MY_PACKAGE_REPLACED"/>
+                <action android:name="android.intent.action.QUICKBOOT_POWERON" />
+                <action android:name="com.htc.intent.action.QUICKBOOT_POWERON"/>
+            </intent-filter>
+        </receiver>
     </application>
     <!-- Required to query activities that can process text, see:
          https://developer.android.com/training/package-visibility and