feat: implement frontend video platform configuration and abstraction

- Add NEXT_PUBLIC_VIDEO_PLATFORM environment variable support
- Create video platform abstraction layer with factory pattern
- Implement Whereby and Jitsi platform providers
- Update room meeting page to use platform-agnostic component
- Add platform display in room management (cards and table views)
- Support single platform per deployment configuration
- Maintain backward compatibility with existing Whereby integration

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

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

www/app/lib/videoPlatforms/factory.ts

@@ -0,0 +1,29 @@
+import { VideoPlatform } from "../../api";
+import { VideoPlatformAdapter } from "./types";
+import { localConfig } from "../../../config-template";
+
+// Platform implementations
+import { WherebyAdapter } from "./whereby/WherebyAdapter";
+import { JitsiAdapter } from "./jitsi/JitsiAdapter";
+
+const platformAdapters: Record<VideoPlatform, VideoPlatformAdapter> = {
+  whereby: WherebyAdapter,
+  jitsi: JitsiAdapter,
+};
+
+export function getVideoPlatformAdapter(
+  platform?: VideoPlatform,
+): VideoPlatformAdapter {
+  const selectedPlatform = platform || localConfig.video_platform;
+
+  const adapter = platformAdapters[selectedPlatform];
+  if (!adapter) {
+    throw new Error(`Unsupported video platform: ${selectedPlatform}`);
+  }
+
+  return adapter;
+}
+
+export function getCurrentVideoPlatform(): VideoPlatform {
+  return localConfig.video_platform;
+}