🐛(frontend) close native PiP window when leaving the room

Force-close PiP on unmount and reset PiP state so next room starts clean.

src/frontend/src/features/pip/components/RoomPiP.tsx

@@ -1,5 +1,6 @@
-import type { ReactNode } from 'react'
+import { useEffect, type ReactNode } from 'react'
 
+import { roomPiPStore } from '@/stores/roomPiP'
 import { DocumentPiPPortal } from './DocumentPiPPortal'
 import { PipView } from './PipView'
 import { useRoomPiP } from '../hooks/useRoomPiP'
@@ -12,6 +13,14 @@ import { useRoomPiP } from '../hooks/useRoomPiP'
 export const RoomPiP = (): ReactNode => {
   const { isOpen, close } = useRoomPiP()
 
+  // Reset PiP state on unmount (e.g. leaving the room) so the next session
+  // starts with PiP closed and doesn't try to auto-reopen without a user gesture.
+  useEffect(() => {
+    return () => {
+      roomPiPStore.isOpen = false
+    }
+  }, [])
+
   const portal = DocumentPiPPortal({
     isOpen,
     onClose: close,

src/frontend/src/features/pip/hooks/useDocumentPiP.ts

@@ -70,6 +70,16 @@ export const useDocumentPiP = ({
     pipWindowRef.current = pipWindow
   }, [pipWindow])
 
+  // Force-close the native PiP window when the hook unmounts (e.g. the user
+  // hangs up and the room is navigated away before `closePiP` could run).
+  useEffect(() => {
+    return () => {
+      const win = pipWindowRef.current
+      if (win && !win.closed) win.close()
+      pipWindowRef.current = null
+    }
+  }, [])
+
   useEffect(() => {
     if (!pipWindow) return