Refactor WebRenderer to use server-side streaming with OGG-FLAC sink

This commit refactors the WebRenderer to use a server-side streaming architecture with OGG-FLAC sink instead of the previous WebSocket-based approach. The changes include:

- Replaced WebSocket communication with HTTP streaming using DirectOggFlacSink
- Implemented a new pipeline architecture with dedicated handlers for UPnP commands
- Added new modules for registration, registry, and streaming
- Updated the renderer to work with a pipeline control system
- Removed old WebSocket session management
- Added support for HTTP streaming with gapless playback
- Updated dependencies and features for the new architecture

The WebRenderer now acts as a MediaRenderer UPnP device that serves audio streams via HTTP endpoints, with commands relayed to the audio pipeline through a new control system.

pmocontrol/src/music_renderer/musicrenderer.rs

@@ -550,8 +550,8 @@ impl MusicRenderer {
                 .map(|prev| !playback_state_equal(prev, &raw_state))
                 .unwrap_or(true);
 
-            // Emit event only for non-transient states to reduce noise
-            if changed && !matches!(raw_state, PlaybackState::Transitioning) {
+            // Emit event for all state changes including Transitioning
+            if changed {
                 let state_clone = raw_state.clone();
                 drop(watched);
                 self.emit_event(RendererEvent::StateChanged {