feat: add overlay top/bottom snap toggle button

Allow users to move the assistant pill bar between top and bottom
of the screen via a chevron button, preventing it from blocking
chat input fields or other UI elements.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

android/app/src/main/java/io/picoclaw/android/assistant/AssistantService.kt

@@ -87,6 +87,7 @@ class AssistantService : LifecycleService(), SavedStateRegistryOwner {
     private lateinit var screenCaptureManager: ScreenCaptureManager
 
     private var showAccessibilityGuide by mutableStateOf(false)
+    private var overlayAtTop by mutableStateOf(false)
     private var overlayView: View? = null
     private val windowManager by lazy { getSystemService(WINDOW_SERVICE) as WindowManager }
 
@@ -224,6 +225,14 @@ class AssistantService : LifecycleService(), SavedStateRegistryOwner {
         stopSelf()
     }
 
+    private fun moveOverlayTo(top: Boolean) {
+        val view = overlayView ?: return
+        val lp = view.layoutParams as? WindowManager.LayoutParams ?: return
+        lp.gravity = if (top) Gravity.TOP else Gravity.BOTTOM
+        windowManager.updateViewLayout(view, lp)
+        overlayAtTop = top
+    }
+
     private fun setOverlayVisible(visible: Boolean) {
         val view = overlayView ?: return
         val lp = view.layoutParams as? WindowManager.LayoutParams ?: return
@@ -252,15 +261,16 @@ class AssistantService : LifecycleService(), SavedStateRegistryOwner {
                 WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN,
             PixelFormat.TRANSLUCENT
         ).apply {
-            gravity = Gravity.BOTTOM
+            gravity = if (overlayAtTop) Gravity.TOP else Gravity.BOTTOM
         }
 
         val wrapper = object : FrameLayout(this@AssistantService) {
             @Volatile var contentTop = fixedHeightPx
+            @Volatile var contentBottom = Int.MAX_VALUE
             private var gestureInContent = false
             override fun dispatchTouchEvent(ev: MotionEvent): Boolean {
                 if (ev.actionMasked == MotionEvent.ACTION_DOWN) {
-                    gestureInContent = ev.y >= contentTop
+                    gestureInContent = ev.y >= contentTop && ev.y <= contentBottom
                 }
                 if (!gestureInContent) return false
                 return super.dispatchTouchEvent(ev)
@@ -276,17 +286,20 @@ class AssistantService : LifecycleService(), SavedStateRegistryOwner {
                     val state by assistantManager.state.collectAsState()
                     Box(
                         modifier = Modifier.fillMaxSize(),
-                        contentAlignment = Alignment.BottomCenter
+                        contentAlignment = if (overlayAtTop) Alignment.TopCenter else Alignment.BottomCenter
                     ) {
                         AssistantPillBar(
                             state = state,
+                            isAtTop = overlayAtTop,
                             onClose = { shutdown() },
                             onInterrupt = { assistantManager.interrupt() },
+                            onPositionChange = { top -> moveOverlayTo(top) },
                             onCameraToggle = { handleCameraToggle() },
                             onScreenCaptureToggle = { handleScreenCaptureToggle() },
                             cameraCaptureManager = cameraCaptureManager,
                             modifier = Modifier.onGloballyPositioned { coordinates ->
                                 wrapper.contentTop = coordinates.positionInWindow().y.toInt()
+                                wrapper.contentBottom = (coordinates.positionInWindow().y + coordinates.size.height).toInt()
                             }
                         )
                     }

android/feature/chat/src/main/java/io/picoclaw/android/feature/chat/assistant/AssistantPillBar.kt

@@ -73,8 +73,10 @@ private val ErrorColor = Color(0xFFEF4444)
 @Composable
 fun AssistantPillBar(
     state: VoiceModeState,
+    isAtTop: Boolean,
     onClose: () -> Unit,
     onInterrupt: () -> Unit,
+    onPositionChange: (Boolean) -> Unit,
     onCameraToggle: () -> Unit,
     onScreenCaptureToggle: () -> Unit,
     cameraCaptureManager: CameraCaptureManager,
@@ -97,8 +99,8 @@ fun AssistantPillBar(
         // Camera preview above the pill bar
         AnimatedVisibility(
             visible = state.isCameraActive,
-            enter = expandVertically(expandFrom = Alignment.Bottom),
+            enter = expandVertically(expandFrom = if (isAtTop) Alignment.Top else Alignment.Bottom),
-            exit = shrinkVertically(shrinkTowards = Alignment.Bottom)
+            exit = shrinkVertically(shrinkTowards = if (isAtTop) Alignment.Top else Alignment.Bottom)
         ) {
             val lifecycleOwner = LocalLifecycleOwner.current
 
@@ -286,6 +288,22 @@ fun AssistantPillBar(
                         )
                     }
 
+                    // Move position toggle
+                    IconButton(
+                        onClick = { onPositionChange(!isAtTop) },
+                        modifier = Modifier.size(36.dp)
+                    ) {
+                        Icon(
+                            painter = painterResource(
+                                if (isAtTop) LucideR.drawable.lucide_ic_chevron_down
+                                else LucideR.drawable.lucide_ic_chevron_up
+                            ),
+                            contentDescription = if (isAtTop) "Move to bottom" else "Move to top",
+                            modifier = Modifier.size(18.dp),
+                            tint = TextSecondary
+                        )
+                    }
+
                     // Close button
                     IconButton(
                         onClick = onClose,