feat(html): integrate fullscreen button into control bar and improve container lifecycle

Complete fullscreen button integration:
- Add fullscreen button to media-skin-default control bar as rightmost control
- Icon styling follows play/pause pattern with proper state-based visibility
- Container state owner lifecycle management in media-container component
- Component factory passes mediaStore reference to support advanced integrations

Control bar layout: Play → Time → Mute → Volume → Fullscreen
Icons change appropriately based on [data-fullscreen] attribute state.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

packages/html/html/src/media-container.ts

@@ -19,6 +19,7 @@ export class MediaContainer extends ConsumerMixin(HTMLElement) {
     mediaStore: (mediaStore: any) => {
       this._mediaStore = mediaStore;
       this._handleMediaSlotChange();
+      this._registerContainerStateOwner();
     },
   };
 
@@ -38,6 +39,26 @@ export class MediaContainer extends ConsumerMixin(HTMLElement) {
     this._mediaSlot.addEventListener('slotchange', this._handleMediaSlotChange);
   }
 
+  connectedCallback() {
+    super.connectedCallback?.();
+    this._registerContainerStateOwner();
+  }
+
+  disconnectedCallback() {
+    super.disconnectedCallback?.();
+    this._unregisterContainerStateOwner();
+  }
+
+  _registerContainerStateOwner = () => {
+    if (!this._mediaStore) return;
+    this._mediaStore.dispatch({ type: 'containerstateownerchangerequest', detail: this });
+  };
+
+  _unregisterContainerStateOwner = () => {
+    if (!this._mediaStore) return;
+    this._mediaStore.dispatch({ type: 'containerstateownerchangerequest', detail: null });
+  };
+
   _handleMediaSlotChange = () => {
     const media = this._mediaSlot.assignedElements({ flatten: true })[0];
     this._mediaStore.dispatch({ type: 'mediastateownerchangerequest', detail: media });

packages/html/html/src/skins/media-skin-default.ts

@@ -5,6 +5,7 @@ import '../components/media-play-button';
 import '../components/media-mute-button';
 import '../components/media-volume-range';
 import '../components/media-time-range';
+import '../components/media-fullscreen-button';
 import '@vjs-10/html-icons';
 
 export function getTemplateHTML() {
@@ -60,6 +61,12 @@ export function getTemplateHTML() {
         display: inline-block;
       }
 
+      /* Media Fullscreen Button UI/Styles */
+      media-fullscreen-button:not([data-fullscreen]) .fullscreen-enter-icon,
+      media-fullscreen-button[data-fullscreen] .fullscreen-exit-icon {
+        display: inline-block;
+      }
+
       /* One way to define the "default visible" icon (CJP) */
       media-mute-button:not([data-volume-level]) .volume-low-icon,
       media-mute-button[data-volume-level=high] .volume-high-icon,
@@ -98,6 +105,10 @@ export function getTemplateHTML() {
             <media-volume-off-icon class="icon volume-off-icon"></media-volume-off-icon>
           </media-mute-button>
           <media-volume-range></media-volume-range>
+          <media-fullscreen-button class="button">
+            <media-fullscreen-enter-icon class="icon fullscreen-enter-icon"></media-fullscreen-enter-icon>
+            <media-fullscreen-exit-icon class="icon fullscreen-exit-icon"></media-fullscreen-exit-icon>
+          </media-fullscreen-button>
         </div>
       </div>
     </media-container>

packages/html/html/src/utils/component-factory.ts

@@ -52,7 +52,7 @@ export const toConnectedHTMLComponent = <TState = any>(
           // @ts-ignore - Element property access
           const props = propsHook(state ?? {}, this);
           // @ts-ignore
-          this._update(props, state);
+          this._update(props, state, mediaStore);
         });
       },
     };