v0.40.0-tor.4

One fix for the first seconds after a start.

Images (linux/amd64; this release also moves latest):

• ghcr.io/highda/redlib-tor-api:v0.40.0-tor.4
• ghcr.io/highda/redlib-tor-api-teddit:v0.40.0-tor.4

Fixed:

• Until Redlib has its first Reddit token, requests now answer 503 "Redlib is still connecting to Reddit" with Retry-After: 30. In v0.40.0-tor.3 the message came wrapped as "Couldn't send request to Reddit", so clients got 502, /healthz/reddit counted each one as a network failure (a watchdog could see "failing" right after a restart) and each was retried once for nothing. Seen on production after the tor.3 upgrade.

Tested: cargo tests (99, offline subset) and a binary that cannot reach Tor: web pages and /raw answer 503 with Retry-After, and /healthz/reddit stays at "no Reddit requests yet".