* fix: fall back to enroll token when pilot tunnel JWT is rejected
On HTTP 401/404 upgrade rejection, delete stale pilot.jwt and retry with SENCHO_ENROLL_TOKEN.
* test: import pilot agent module after DATA_DIR is set in fallback test
The auth-fallback test statically imported pilot/agent, which freezes its
pilot.jwt path from DATA_DIR at module load, before setupTestDb redirects
DATA_DIR to a writable temp dir. On the Linux CI runner the path resolved
to a non-writable /app/data, so persistToken silently failed and the
round-trip assertion read null. Import the module dynamically in beforeAll
after setupTestDb, matching the sibling unit test.
* fix: remove unexpected-response listener that blocked pilot reconnect
The ws library skips abortHandshake when an unexpected-response listener
exists, so error and close never fire and the agent hangs in CONNECTING.
Detect auth rejection via the abortHandshake error message instead; the
close handler already performs enroll-token fallback and reconnect.
Anso