feat: Add database migrations and auth system

- Add Alembic for database migrations
- Implement user authentication system
- Update frontend styles and components
- Add new test audio functionality
- Update stream management and UI

middleware.py

@@ -0,0 +1,73 @@
+"""Custom middleware for the dicta2stream application"""
+import time
+from fastapi import Request, HTTPException
+from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
+from starlette.responses import Response
+from starlette.types import ASGIApp
+
+class RateLimitMiddleware(BaseHTTPMiddleware):
+    """Middleware to implement rate limiting"""
+    def __init__(self, app: ASGIApp, limit: int = 100, window: int = 60):
+        super().__init__(app)
+        self.limit = limit
+        self.window = window
+        self.requests = {}
+
+    async def dispatch(self, request: Request, call_next: RequestResponseEndpoint) -> Response:
+        # Get client IP
+        if "x-forwarded-for" in request.headers:
+            ip = request.headers["x-forwarded-for"].split(",")[0]
+        else:
+            ip = request.client.host or "unknown"
+        
+        # Get current timestamp
+        current_time = int(time.time())
+        
+        # Clean up old entries
+        self.requests = {
+            k: v 
+            for k, v in self.requests.items() 
+            if current_time - v["timestamp"] < self.window
+        }
+        
+        # Check rate limit
+        if ip in self.requests:
+            self.requests[ip]["count"] += 1
+            if self.requests[ip]["count"] > self.limit:
+                raise HTTPException(
+                    status_code=429, 
+                    detail="Too many requests. Please try again later."
+                )
+        else:
+            self.requests[ip] = {"count": 1, "timestamp": current_time}
+        
+        # Process the request
+        response = await call_next(request)
+        return response
+
+
+class SecurityHeadersMiddleware(BaseHTTPMiddleware):
+    """Middleware to add security headers to responses"""
+    async def dispatch(self, request: Request, call_next):
+        response = await call_next(request)
+        
+        # Add security headers
+        response.headers["X-Content-Type-Options"] = "nosniff"
+        response.headers["X-Frame-Options"] = "DENY"
+        response.headers["X-XSS-Protection"] = "1; mode=block"
+        response.headers["Referrer-Policy"] = "strict-origin-when-cross-origin"
+        
+        # Content Security Policy
+        csp_parts = [
+            "default-src 'self'",
+            "script-src 'self' 'unsafe-inline'",
+            "style-src 'self' 'unsafe-inline'",
+            "img-src 'self' data:",
+            "media-src 'self' blob: data:",
+            "connect-src 'self' https: wss:",
+            "frame-ancestors 'none'"
+        ]
+        
+        response.headers["Content-Security-Policy"] = "; ".join(csp_parts)
+        
+        return response