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/activity_main.xml

@@ -20,16 +20,26 @@
                 android:id="@+id/toolbar"
                 android:layout_width="match_parent"
                 android:layout_height="?attr/actionBarSize"
-                app:title="@string/app_name"
-                app:titleTextColor="@android:color/white"
-                android:background="@color/colorPrimary">
+                android:background="@color/colorPrimary"
+                app:contentInsetStart="12dp">
+
+                <TextView
+                    android:id="@+id/toolbar_title"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:text="@string/app_name"
+                    android:textColor="@android:color/white"
+                    android:textSize="18sp"
+                    android:maxLines="1"
+                    android:ellipsize="end"
+                    android:gravity="center_vertical" />
 
                 <ImageButton
                     android:id="@+id/btn_refresh"
                     android:layout_width="40dp"
                     android:layout_height="40dp"
                     android:layout_gravity="end"
-                    android:layout_marginEnd="4dp"
                     android:src="@drawable/ic_refresh"
                     android:background="?attr/selectableItemBackgroundBorderless"
                     android:contentDescription="@string/refresh" />
@@ -39,7 +49,6 @@
                     android:layout_width="40dp"
                     android:layout_height="40dp"
                     android:layout_gravity="end"
-                    android:layout_marginEnd="4dp"
                     android:src="@drawable/ic_settings"
                     android:background="?attr/selectableItemBackgroundBorderless"
                     android:contentDescription="@string/settings" />