fix(core): guard webkit pip exit and fix api check order

- Check standard `requestPictureInPicture` before webkit fallback in
  `isPictureInPictureEnabled`, matching `requestPictureInPicture` order.
- Guard `exitPictureInPicture` webkit path with presentation mode check
  to avoid accidentally exiting fullscreen.
- Update fullscreen button test to expect error propagation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mihar-22

packages/core/src/core/ui/fullscreen-button/tests/fullscreen-button-core.test.ts

@@ -158,14 +158,14 @@ describe('FullscreenButtonCore', () => {
       expect(media.requestFullscreen).not.toHaveBeenCalled();
     });
 
-    it('catches fullscreen errors silently', () => {
+    it('propagates fullscreen errors to caller', async () => {
       const core = new FullscreenButtonCore();
       const media = createMediaState({
         requestFullscreen: vi.fn(async () => {
           throw new Error('permission denied');
         }),
       });
-      expect(() => core.toggle(media)).not.toThrow();
+      await expect(core.toggle(media)).rejects.toThrow('permission denied');
     });
   });
 });

packages/core/src/dom/presentation/pip.ts

@@ -7,14 +7,14 @@ export function isPictureInPictureEnabled(media: Media): boolean {
   const video = resolveHTMLVideoElement(media);
   if (!video) return false;
 
-  if (isWebKitVideoElement(video)) {
-    return video.webkitSupportsPresentationMode('picture-in-picture');
-  }
-
   if (isFunction(video.requestPictureInPicture)) {
     return true;
   }
 
+  if (isWebKitVideoElement(video)) {
+    return video.webkitSupportsPresentationMode('picture-in-picture');
+  }
+
   return false;
 }
 
@@ -53,7 +53,7 @@ export function requestPictureInPicture(media: Media): Promise<unknown> {
 export function exitPictureInPicture(media?: Media): Promise<void> {
   const video = media && resolveHTMLVideoElement(media);
 
-  if (isWebKitVideoElement(video)) {
+  if (isWebKitVideoElement(video) && video.webkitPresentationMode === 'picture-in-picture') {
     return Promise.resolve(video.webkitSetPresentationMode('inline'));
   }