* fix(server): restore gitnexus serve startup under Express 5
Express 5 rejects app.options('*'), which broke CI e2e when the backend
failed to start. Move PNA middleware before cors so preflight responses
include Access-Control-Allow-Private-Network, and add regression tests.
Co-authored-by: Cursor <cursoragent@cursor.com>
* test(server): address PR review — prettier, ephemeral port, cleanup
- Format integration and rate-limit test files for CI quality/format
- Use OS-assigned port instead of random 47xxx range
- Remove per-test GITNEXUS_HOME temp dir in afterEach
- Use regex for PNA-before-cors structural guard (indent-agnostic)
Co-authored-by: Cursor <cursoragent@cursor.com>
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Co-authored-by: Cursor <cursoragent@cursor.com>
