Implement backend API foundation

- Created FastAPI application with CORS middleware
- Defined Pydantic models (RoleDetectionRequest, RolesResponse, TTSRequest, ErrorResponse)
- Implemented /api/health endpoint
- Set up error handling middleware for validation and general exceptions
- Configured logging with INFO level
- Added test script to verify API functionality
- Validates Requirements: 9.1, 9.2, 9.4

backend/test_api.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+"""Simple test script for API foundation."""
+import urllib.request
+import json
+
+def test_health():
+    """Test health endpoint."""
+    response = urllib.request.urlopen('http://localhost:8001/api/health')
+    data = json.loads(response.read().decode())
+    print(f"✓ Health check: {data}")
+    
+def test_cors():
+    """Test CORS headers."""
+    req = urllib.request.Request('http://localhost:8001/api/health',
+                                  headers={'Origin': 'http://localhost:5173'})
+    response = urllib.request.urlopen(req)
+    cors_origin = response.headers.get('Access-Control-Allow-Origin')
+    cors_creds = response.headers.get('Access-Control-Allow-Credentials')
+    print(f"✓ CORS Origin: {cors_origin}")
+    print(f"✓ CORS Credentials: {cors_creds}")
+
+if __name__ == '__main__':
+    print("Testing API Foundation...")
+    test_health()
+    test_cors()
+    print("\nAll tests passed!")