fix(mobile): keep Android content clear of the navigation bar

Android 15+ enforces edge-to-edge, and Capacitor stops padding the WebView
once it can hand the insets to the page instead — so the app draws under
the gesture/navigation bar. Only the top inset was ever consumed: full
cover surfaces ignored the bottom one entirely, which is why a settings
list ran under the bar, and the chat shell reserved half of it, which is
enough for a home indicator but not for a bar that swallows taps.

Reserve the full inset in the shell on Android and give the surfaces that
own the bottom edge — fullscreen surfaces, the workspace drawer, bottom
sheets — an opt-in class that pads them. The sessions drawer already did
this through its footer, so it stays as it is. Capacitor reports a zero
bottom inset while the keyboard is up, so none of this stacks with the
keyboard inset. iOS deliberately keeps its softer visual inset.

Testing: package type-check and lint; drove the mobile surface in a
browser with the Android platform class and a simulated 48px inset (shell
and surfaces reserve exactly that, drawer footer unchanged, and removing
the class returns every surface to zero).

packages/ui/src/apps/MobileFullscreenSurface.tsx

@@ -175,7 +175,7 @@ export const MobileFullscreenSurface: React.FC<MobileFullscreenSurfaceProps> = (
         'flex flex-col bg-background text-foreground',
         isDialog
           ? 'h-[min(88dvh,860px)] w-full max-w-[720px] overflow-hidden rounded-2xl border border-border/70 shadow-[0_24px_64px_rgb(0_0_0_/_0.32)]'
-          : 'oc-keyboard-inset-surface fixed inset-0 z-50',
+          : 'oc-keyboard-inset-surface oc-bottom-safe-surface fixed inset-0 z-50',
       )}
       style={isDialog ? {
         // Scale/fade instead of the push slide: the card is not a navigation
@@ -249,7 +249,7 @@ export const MobileFullscreenSurface: React.FC<MobileFullscreenSurfaceProps> = (
 
   return createPortal(
     <div
-      className="oc-keyboard-inset-surface fixed inset-0 z-50 flex items-center justify-center p-4 transition-opacity duration-200 ease-out"
+      className="oc-keyboard-inset-surface oc-bottom-safe-surface fixed inset-0 z-50 flex items-center justify-center p-4 transition-opacity duration-200 ease-out"
       style={{
         background: 'rgb(0 0 0 / 0.45)',
         opacity: entered ? 1 : 0,

packages/ui/src/apps/MobileWorkspaceDrawer.tsx

@@ -295,7 +295,7 @@ export const MobileWorkspaceDrawer: React.FC<{
       aria-modal="true"
       aria-label={t('mobile.header.openWorkspaceAria')}
       aria-hidden={!open}
-      className="oc-keyboard-inset-surface fixed inset-0 z-50 flex flex-col bg-background text-foreground"
+      className="oc-keyboard-inset-surface oc-bottom-safe-surface fixed inset-0 z-50 flex flex-col bg-background text-foreground"
       style={{
         paddingTop: 'var(--oc-safe-area-top, 0px)',
         // Settled state drops the transform entirely so the drawer isn't kept

packages/ui/src/components/ui/MobileOverlayPanel.tsx

@@ -112,7 +112,7 @@ export const MobileOverlayPanel: React.FC<MobileOverlayPanelProps> = ({
   const content = (
     <div
       className={cn(
-        'oc-keyboard-inset-surface fixed inset-0 z-[60] flex flex-col bg-[rgb(0_0_0_/_0.45)] transition-opacity duration-200 ease-out',
+        'oc-keyboard-inset-surface oc-bottom-safe-surface fixed inset-0 z-[60] flex flex-col bg-[rgb(0_0_0_/_0.45)] transition-opacity duration-200 ease-out',
         !enterSettled && 'oc-keyboard-inset-snap',
         entered ? 'opacity-100' : 'opacity-0',
       )}

packages/ui/src/styles/mobile.css

@@ -470,6 +470,22 @@
   padding-top: var(--oc-safe-area-top);
 }
 
+/* Android 15+ enforces edge-to-edge, and once the WebView can read the insets
+   itself Capacitor stops padding the view and just hands them over — so the app
+   draws under the navigation/gesture bar and every full-cover surface has to
+   keep its own content clear of it. Marked surfaces opt in through
+   .oc-bottom-safe-surface; iOS deliberately stays on its softer visual inset,
+   where the home indicator is a thin overlay rather than a bar that eats taps.
+   Capacitor reports a zero bottom inset while the keyboard is up, so this never
+   stacks with --oc-keyboard-inset. */
+:root.oc-capacitor-app.oc-platform-android {
+  --oc-app-bottom-safe: max(16px, var(--oc-safe-area-bottom));
+}
+
+:root.oc-capacitor-app.oc-platform-android .oc-bottom-safe-surface {
+  padding-bottom: var(--oc-safe-area-bottom);
+}
+
 :root.oc-capacitor-app.oc-platform-android [data-sonner-toaster][data-y-position='top'] {
   top: calc(var(--oc-safe-area-top) + 16px) !important;
 }