c512534bfa
Three changes to fix the immediate-logout issue reported by multiple Docker users: 1. Add explicit `credentials: 'same-origin'` to the login fetch call. This was the only fetch in the entire codebase missing it. While modern browsers default to 'same-origin', some privacy configs or older engines may default to 'omit', silently dropping Set-Cookie headers from the login response. 2. Post-login cookie verification: after a successful login, the frontend now checks that the CSRF cookie (non-HttpOnly, readable by JS) was actually stored before redirecting. If the browser rejected the cookies, a clear error message is shown explaining the OXICLOUD_COOKIE_SECURE / HTTP mismatch. 3. Server-side diagnostic: the login handler now warns in logs when Secure cookies are set on a request that didn't arrive via HTTPS (no X-Forwarded-Proto: https header), pointing admins to the OXICLOUD_COOKIE_SECURE=false fix. Root cause: users who set OXICLOUD_BASE_URL=https://... (or have OXICLOUD_COOKIE_SECURE=true) but access via plain HTTP get cookies with the Secure flag, which browsers silently reject over HTTP.