Add CORS Logging Middleware and Fix CORS Configuration

[KnellBalm]

Added CORSLoggingMiddleware to backend/common/middleware.py and registered it in backend/main.py to debug production CORS issues. Verified that the cloud origin regex and allowed origins list are correct using tests/test_cors_config.py. This change also triggers a redeployment which might resolve stale configuration issues.

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PR created automatically by Jules for task 8824180182849832873 started by @KnellBalm

Summary by Sourcery

Add middleware to log CORS-related request and response details to aid debugging of CORS issues in production.

Enhancements:

• Introduce CORSLoggingMiddleware to capture origin and CORS header information on incoming requests.
• Register the CORS logging middleware in the main application so CORS requests are logged in production.

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[sourcery-ai]

Reviewer's Guide

Adds a CORS logging middleware to observe and debug CORS behavior in production and wires it into the FastAPI app after the existing CORS middleware, without changing the underlying CORS config itself.

Sequence diagram for CORS request handling with CORSLoggingMiddleware

sequenceDiagram
    actor Browser
    participant FastAPIApp
    participant CORSLoggingMiddleware
    participant CORSMiddleware
    participant EndpointHandler

    Browser->>FastAPIApp: HTTP request with Origin header
    FastAPIApp->>CORSLoggingMiddleware: dispatch(request, call_next)
    CORSLoggingMiddleware->>CORSMiddleware: call_next(request)
    CORSMiddleware->>EndpointHandler: Process request
    EndpointHandler-->>CORSMiddleware: Response
    CORSMiddleware-->>CORSLoggingMiddleware: Response with CORS headers
    CORSLoggingMiddleware->>CORSLoggingMiddleware: Read Origin and CORS headers
    alt access_control_allow_origin present
        CORSLoggingMiddleware->>CORSLoggingMiddleware: logger.info CORS Success
    else access_control_allow_origin missing
        CORSLoggingMiddleware->>CORSLoggingMiddleware: logger.warning CORS Missing Header
    end
    CORSLoggingMiddleware-->>FastAPIApp: Final response
    FastAPIApp-->>Browser: HTTP response with CORS headers

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Class diagram for new CORSLoggingMiddleware

classDiagram
    class BaseHTTPMiddleware {
    }

    class CORSLoggingMiddleware {
        +dispatch(request, call_next)
    }

    BaseHTTPMiddleware <|-- CORSLoggingMiddleware

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File-Level Changes

Change	Details	Files
Introduce CORSLoggingMiddleware to log CORS-related request/response details for debugging.	Add CORSLoggingMiddleware class extending BaseHTTPMiddleware to inspect requests with an Origin header Log successful CORS responses (when Access-Control-Allow-Origin is present) at info level with origin and path Log missing CORS headers at warning level including origin, path, method, and response status	backend/common/middleware.py
Register CORSLoggingMiddleware after existing CORS middleware in app setup.	Add CORSLoggingMiddleware to the FastAPI app so it wraps the existing CORSMiddleware and sees requests first Keep existing CORS configuration (origins, regex, methods, headers) unchanged while enabling logging	backend/main.py

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[sourcery-ai]

Hey - I've left some high level feedback:

• CORSLoggingMiddleware calls get_logger on every request; consider instantiating the logger once at module or class level to avoid repeated lookups on the hot path.
• Logging every successful CORS response at info level may be too noisy in production; you might want to downgrade success logs to debug and keep warning only for missing headers.
• Since CORSLoggingMiddleware logs the Origin header for all requests with an origin, verify that this doesn’t expose sensitive or high-volume data in your central logs and consider adding sampling or filtering if needed.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- `CORSLoggingMiddleware` calls `get_logger` on every request; consider instantiating the logger once at module or class level to avoid repeated lookups on the hot path.
- Logging every successful CORS response at `info` level may be too noisy in production; you might want to downgrade success logs to `debug` and keep `warning` only for missing headers.
- Since `CORSLoggingMiddleware` logs the `Origin` header for all requests with an origin, verify that this doesn’t expose sensitive or high-volume data in your central logs and consider adding sampling or filtering if needed.

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