Root cause: post_update_to_api set POST_UPDATE_DONE=true even after
all 3 retry attempts failed (curl timeout, API error). This prevented
the EXIT trap (api_exit_script) from retrying with fresh attempts.
Changes:
- Only set POST_UPDATE_DONE=true on actual HTTP 2xx success
- If all 3 attempts fail, EXIT trap gets 3 more fresh attempts
- Increase timeout from 5s to 10s for final status updates (STATUS_TIMEOUT)
Progress pings keep 5s (TELEMETRY_TIMEOUT) since they're lightweight
- post_update_to_api_extended: add proper retry logic + HTTP code check
(was fire-and-forget with no retry)
5f13d29c57