ADFA-4887: WebView nav — touch-based auto-hide + Home becomes Fullscreen

- Restore auto-hide from the LAST touch: resetTimer now reschedules the hide after
  AUTO_HIDE_MS (4s) instead of only cancelling it; GestureWebView notifies the host on
  each touch (setOnUserInteraction) so content touches count, and the countdown starts on
  load. The handle brings the bar back; btnHideNav still hides manually.
- Repurpose Home as a Fullscreen toggle (no in-WebView home page anymore): enter full
  immersive (system bars hidden via WindowInsetsControllerCompat) and hide our bar too,
  but keep it recoverable via the handle; press again to exit. Glyph swapped to a
  fullscreen mark (Material 3 icon + contentDescription land in ADFA-4886).

Author: luisguzman-adfa

controller/app/src/main/java/org/iiab/controller/PortalActivity.java

@@ -69,6 +69,8 @@ public class PortalActivity extends AppCompatActivity {
 
     private GestureWebView webView;
     private org.iiab.controller.redesign.FqrController fqr;   // ADFA-4879: FQR maps (only on /maps/)
+    private static final long AUTO_HIDE_MS = 4000L;   // ADFA-4887: nav-bar auto-hide after inactivity
+    private boolean fullscreenOn = false;             // ADFA-4887: Home button toggles fullscreen
     // pdf.js builds advertised by /pdfjs/manifest.json (loaded off the main thread).
     // Empty until loaded / when the box serves none -> PDFs fall back to download.
     private volatile List<PdfViewerBuild> pdfViewerBuilds = Collections.emptyList();
@@ -100,16 +102,15 @@ protected void onCreate(Bundle savedInstanceState) {
         Button btnExit = findViewById(R.id.btnExit);
         Button btnForward = findViewById(R.id.btnForward);
 
-        // --- PERSISTENT BAR ---
-        // Keep the nav bar (with Exit) visible so a non-technical user always has an
-        // obvious way out. The handle is only used after a manual hide (btnHideNav).
+        // --- NAV BAR (auto-hide after inactivity) ---
+        // Visible on entry; hides after AUTO_HIDE_MS with no interaction, measured from the LAST
+        // touch. The handle (⌃) brings it back; btnHideNav hides it manually.
         bottomNav.post(() -> {
             bottomNav.setTranslationY(0);
             bottomNav.setVisibility(View.VISIBLE);
         });
         btnHandle.setVisibility(View.GONE);
 
-        // --- AUTO-HIDE TIMER ---
         Handler hideHandler = new Handler(Looper.getMainLooper());
 
         Runnable hideRunnable = () -> {
@@ -118,8 +119,13 @@ protected void onCreate(Bundle savedInstanceState) {
             btnHandle.animate().alpha(1f).setDuration(150);
         };
 
-        // Persistent bar: never auto-hide. Cancel any pending hide; only btnHideNav hides.
-        Runnable resetTimer = () -> hideHandler.removeCallbacks(hideRunnable);
+        // Reschedule the hide on every interaction -> auto-hide from the LAST touch, not the first.
+        Runnable resetTimer = () -> {
+            hideHandler.removeCallbacks(hideRunnable);
+            hideHandler.postDelayed(hideRunnable, AUTO_HIDE_MS);
+        };
+        webView.setOnUserInteraction(resetTimer);   // content touches count as interaction too
+        resetTimer.run();                            // start the initial countdown
 
         // --- HANDLE LOGIC (Show Bar) ---
         btnHandle.setOnClickListener(v -> {
@@ -141,8 +147,23 @@ protected void onCreate(Bundle savedInstanceState) {
         // Resolve the target URL once (domain), surviving rotation via the ViewModel.
         final String finalTargetUrl = vm.targetUrl(getIntent().getStringExtra("TARGET_URL"));
 
+        // ADFA-4887: there is no in-WebView home page anymore, so Home is a Fullscreen toggle.
+        // Enters full immersive (system bars hidden) and hides our bar too — but the bar stays
+        // recoverable via the handle. Press again to exit.
         btnHome.setOnClickListener(v -> {
-            webView.loadUrl(finalTargetUrl);
+            fullscreenOn = !fullscreenOn;
+            androidx.core.view.WindowInsetsControllerCompat wic =
+                    androidx.core.view.WindowCompat.getInsetsController(getWindow(), getWindow().getDecorView());
+            if (fullscreenOn) {
+                wic.setSystemBarsBehavior(
+                        androidx.core.view.WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);
+                wic.hide(androidx.core.view.WindowInsetsCompat.Type.systemBars());
+                hideRunnable.run();   // hide our bar too (still recoverable via the handle)
+            } else {
+                wic.show(androidx.core.view.WindowInsetsCompat.Type.systemBars());
+                btnHandle.animate().alpha(0f).setDuration(150).withEndAction(() -> btnHandle.setVisibility(View.GONE));
+                bottomNav.animate().translationY(0).setDuration(250);
+            }
             resetTimer.run();
         });
 

controller/app/src/main/java/org/iiab/controller/portal/presentation/GestureWebView.java

@@ -28,6 +28,7 @@ public class GestureWebView extends WebView {
     public static final String TAG = "IIAB-GestureWV";
 
     private boolean gestureLogging = false;
+    private Runnable onUserInteraction;   // ADFA-4887: notified on each touch (nav-bar auto-hide)
 
     public GestureWebView(Context context) { super(context); }
     public GestureWebView(Context context, AttributeSet attrs) { super(context, attrs); }
@@ -36,10 +37,15 @@ public class GestureWebView extends WebView {
     /** Enable verbose touch logging (debug builds only). */
     public void setGestureLogging(boolean enabled) { this.gestureLogging = enabled; }
 
+    /** Called on every touch so the host can reset UI timers (e.g. nav-bar auto-hide from last touch). */
+    public void setOnUserInteraction(Runnable r) { this.onUserInteraction = r; }
+
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         final int pointers = event.getPointerCount();
 
+        if (onUserInteraction != null) onUserInteraction.run();
+
         // Two or more fingers: keep the gesture for the web content (the map),
         // so an ancestor (pager/scroll) can't hijack a tilt/rotate/pinch.
         if (pointers >= 2) {

controller/app/src/main/res/layout/activity_portal.xml

@@ -61,12 +61,14 @@
                 style="?android:attr/buttonBarButtonStyle"
                 android:textColor="?android:attr/textColorPrimary" />
 
+            <!-- ADFA-4887: repurposed as a Fullscreen toggle (no in-WebView home page anymore).
+                 Material 3 icon + contentDescription land in ADFA-4886. -->
             <Button
                 android:id="@+id/btnHome"
                 android:layout_width="0dp"
                 android:layout_height="wrap_content"
                 android:layout_weight="1"
-                android:text="🏠"
+                android:text="⛶"
                 android:textSize="20sp"
                 style="?android:attr/buttonBarButtonStyle"
                 android:textColor="?android:attr/textColorPrimary" />