feat(web): add support for casting (#18231)

* recreate #13966

* gcast button works

* rewrote gcast-player to be GCastDestination and CastManager manages the interface between UI and casting destinations

* remove unneeded imports

* add "Connected to" translation

* Remove css for cast launcher

* fix tests

* fix doc tests

* fix the receiver application ID

* remove casting app ID

* remove cast button from nav bar

It is now present at the following locations:

- shared link album and single asset views
- asset viewer (normal user)
- album view (normal user)

* part 1 of fixes from @danieldietzler code review

* part 2 of code review changes from @danieldietzler and @jsram91

* cleanup documentation

* onVideoStarted missing callback

* add token expiry validation

* cleanup logic and logging

* small cleanup

* rename to ICastDestination

* cast button changes

web/src/lib/components/asset-viewer/photo-viewer.svelte

@@ -23,6 +23,7 @@
   import { fade } from 'svelte/transition';
   import LoadingSpinner from '../shared-components/loading-spinner.svelte';
   import { NotificationType, notificationController } from '../shared-components/notification/notification';
+  import { castManager } from '$lib/managers/cast-manager.svelte';
 
   interface Props {
     asset: AssetResponseDto;
@@ -147,6 +148,27 @@
     return AssetMediaSize.Preview;
   });
 
+  $effect(() => {
+    if (assetFileUrl) {
+      // this can't be in an async context with $effect
+      void cast(assetFileUrl);
+    }
+  });
+
+  const cast = async (url: string) => {
+    if (!url || !castManager.isCasting) {
+      return;
+    }
+    const fullUrl = new URL(url, globalThis.location.href);
+
+    try {
+      await castManager.loadMedia(fullUrl.href);
+    } catch (error) {
+      handleError(error, 'Unable to cast');
+      return;
+    }
+  };
+
   const onload = () => {
     imageLoaded = true;
     assetFileUrl = imageLoaderUrl;