🐛(frontend) filter expected user actions from PiP error reporting

The Picture-in-Picture error handler was reporting every error to
PostHog, including the ones triggered when the user intentionally
closes or cancels the PiP window.

Only report unexpected errors, so PostHog no longer receives noise
from normal user interactions.

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

@@ -61,14 +61,20 @@ export const usePictureInPicture = () => {
       if (!IS_PIP_SUPPORTED) return null
       if (isOpen) return null
 
+      let pipWindow: Window
       try {
-        const pipWindow =
+        pipWindow =
           await // eslint-disable-next-line @typescript-eslint/no-explicit-any
           (window as any).documentPictureInPicture.requestWindow({
             width,
             height,
           })
+      } catch {
+        // Avoid unhandled rejections if the user blocks or closes the request.
+        return null
+      }
 
+      try {
         initializeTitleAndLanguage(pipWindow, t('title'))
         initializePortalContainer(pipWindow)
         syncStyles(pipWindow)
@@ -86,10 +92,10 @@ export const usePictureInPicture = () => {
         })
         documentPictureInPictureStore.window = ref(pipWindow)
       } catch (error) {
-        // Avoid unhandled rejections if the user blocks or closes the request.
         reportError('generic_failure', error, {
-          context: 'Failed to open Picture-in-Picture window',
+          context: 'pip_init_failure',
         })
+        pipWindow.close()
         return null
       }
     },