Cookie authentication: first request fails, requires restart when cookies expire

[connelldave]

Cookie authentication: first request fails, requires restart when cookies expire

Problem

When using GITLAB_AUTH_COOKIE_PATH with an auth proxy:

1. First request fails - Auth proxies redirect and set cookies on the first request. The MCP server's first real request fails because the session isn't established yet.

2. Server restart required when cookies expire - Cookies are loaded once at startup. If an external process refreshes expired cookies (e.g., every 2 hours), the MCP server keeps using stale cookies until restarted.

Expected behavior

• First request should succeed (after automatic session warmup)
• Cookie file changes should be detected and reloaded automatically

Environment

• Using GITLAB_AUTH_COOKIE_PATH with cookie-based proxy authentication
• Cookies managed by external process that refreshes them periodically

[connelldave]

#315