feat: full-featured Android app — not just public view

Rewrote the Android WebView app to load the entire meal-tracker
web application, not just the public sharing page:

- User configures their server base URL (e.g. https://meals.example.com)
- Full login/register, dashboard, meal responses, history, settings
- Cookie/session support — login persists across app restarts
- Dynamic toolbar title from page
- 'Clear Data' button in settings to wipe cookies/cache/sessions
- Server URL auto-normalized (trailing slash stripped, https:// added)
- Back button navigates within WebView history
- Swipe-to-refresh, loading bar, network error handling

android/app/src/main/res/layout/dialog_settings.xml

@@ -12,18 +12,19 @@
         android:text="@string/url_label"
         android:textSize="14sp"
         android:textColor="@android:color/darker_gray"
-        android:paddingBottom="4dp" />
+        android:paddingBottom="6dp" />
 
     <EditText
         android:id="@+id/url_input"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:inputType="textUri"
-        android:hint="https://meals.example.com/public/..."
+        android:hint="https://meals.example.com"
         android:padding="12dp"
         android:background="@android:drawable/edit_text"
         android:textSize="14sp"
-        android:importantForAutofill="no" />
+        android:importantForAutofill="no"
+        android:autofillHints="no" />
 
     <TextView
         android:id="@+id/url_hint"