fix: issues in error handling

[ikeshav26]

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🔄 Pull Request (Concise)

# fix: WebSocket error handling causes crashes and log pollution

## 📋 Summary
Fixes critical error handling in WebSocket streaming that causes crashes on normal disconnects and silent failures on errors.

## 🐛 Problems Fixed

**Issue 1: RuntimeError on every disconnect**
- Users stop playback → server logs `RuntimeError: Cannot call "send" once...`
- Fix: Wrap `ws.close()` in try-catch

**Issue 2: Unhandled exceptions**
- Only catches `WebSocketDisconnect`, not OOM/model errors
- Silent failures, no user feedback, resources leak
- Fix: Add generic exception handler

## 🔧 Changes

# 1. Safe WebSocket close
try:
    if ws.client_state == WebSocketState.CONNECTED:
        await ws.close()
except Exception as e:
    print(f"Error closing websocket: {e}")

# 2. Catch all streaming errors
except Exception as e:
    print(f"Error in websocket stream: {e}")
    traceback.print_exc()
    enqueue_log("backend_error", message=str(e))
    stop_signal.set()

[ikeshav26]

@YaoyaoChang can u please review this PR..!