Add camera functionality for task completion photos

- Add camera picker interface to common ImagePicker.kt
- Implement camera capture for Android using ActivityResultContracts.TakePicture
- Implement camera capture for iOS using UIImagePickerController
- Add camera picker stubs for wasmJs, jsMain, and jvmMain platforms
- Update CompleteTaskDialog to show both "Take Photo" and "Choose from Library" buttons
- Add camera permissions to Android manifest (CAMERA permission, camera intent queries)
- Configure Android FileProvider for camera photo sharing
- Add camera and photo library usage descriptions to iOS Info.plist
- Update iOS CompleteTaskView with native camera picker support
- Fix cancel button in CompleteTaskView using @Environment(\.dismiss)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

composeApp/src/androidMain/AndroidManifest.xml

@@ -2,6 +2,13 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.CAMERA" />
+
+    <queries>
+        <intent>
+            <action android:name="android.media.action.IMAGE_CAPTURE" />
+        </intent>
+    </queries>
 
     <application
         android:allowBackup="true"
@@ -32,6 +39,17 @@
                     android:host="reset-password" />
             </intent-filter>
         </activity>
+
+        <!-- FileProvider for camera photos -->
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
     </application>
 
 </manifest>