chore: Remove websocket dependencies - not used in current version

Removed:
- websocket-client from requirements.txt
- websocket import and HAS_WEBSOCKET check from demo_app.py

The WebSocket streaming UI was already removed, so these dependencies
are no longer needed. Keeping requirements minimal and matching the
working pre-merge version.

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

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

requirements.txt

@@ -28,7 +28,6 @@ fastapi>=0.100
 uvicorn>=0.24
 pydantic>=2.0,<2.12
 pydantic-settings>=2.4
-websocket-client>=1.6
 gradio>=5.0
 
 # Database

src/analyzer/chat/demo_app.py

@@ -29,12 +29,6 @@ except ImportError:
     print("ERROR: httpx not installed. Install with: pip install httpx")
     httpx = None
 
-try:
-    import websocket
-    HAS_WEBSOCKET = True
-except ImportError:
-    HAS_WEBSOCKET = False
-    logging.warning("websocket-client not installed. Install with: pip install websocket-client")
 
 from ..config import load_config
 from ..data_loader import load_current_grants, load_past_winners