feat: add admin login page and authentication API

- Created a new login page for admin access at frontend/admin/login/index.html.
- Implemented form submission with error handling for login credentials.
- Updated frontend/index.html to mute the video player and removed unnecessary Alpine.js data binding.
- Enhanced manifest URL resolution in frontend/src/main.ts to include cache-busting parameters.
- Modified vite.config.ts to include the new admin login page in the build process.
- Updated nginx.conf to handle admin login routing, authentication, and API proxying for admin actions.

frontend/src/main.ts

@@ -29,12 +29,32 @@ function resolveWebSocketBaseUrl() {
 
 function resolveManifestUrl() {
   const configuredUrl = import.meta.env.VITE_PUBLIC_HLS_URL?.trim();
+  const cacheBust = `stream=${Date.now()}`;
+  const sameOriginManifestUrl = new URL(
+    "/hls/playlist.m3u8",
+    window.location.origin,
+  );
+  sameOriginManifestUrl.searchParams.set("stream", cacheBust);
+
+  const allowCrossOriginManifest =
+    import.meta.env.VITE_PUBLIC_HLS_CROSS_ORIGIN?.trim().toLowerCase() ===
+    "true";
 
   if (configuredUrl) {
-    return configuredUrl;
+    const manifestUrl = new URL(configuredUrl);
+    manifestUrl.searchParams.set("stream", cacheBust);
+
+    if (
+      !allowCrossOriginManifest &&
+      manifestUrl.origin !== window.location.origin
+    ) {
+      return sameOriginManifestUrl.toString();
+    }
+
+    return manifestUrl.toString();
   }
 
-  return new URL("/hls/playlist.m3u8", window.location.origin).toString();
+  return sameOriginManifestUrl.toString();
 }
 
 function connectWebSocket(room: string) {