When Bambuddy is restarted mid-print, the first MQTT push from the
printer carries `_previous_gcode_state = None`. The #1304 guard
deliberately suppresses on_print_start on that first push to prevent
duplicate archive creation — but on_print_start is also where
_capture_timelapse_baseline_at_start runs, so the in-memory
_timelapse_baselines dict stays empty for the resumed session.
At PRINT COMPLETE, _scan_for_timelapse_with_retries finds no baseline
and falls into its "take baseline now" fallback. By that point the
printer has already uploaded the in-flight MP4, so the snapshot
includes the new file. Every "Found N files / no new files since
baseline" retry then fails to detect a diff, and the archive ends up
with no timelapse attached — pwostran's report (#1485 follow-up): card
shows the finish snapshot but no video.
Add a sibling callback on_print_running_observed that bambu_mqtt fires
in the "Now tracking RUNNING state" branch when on_print_start was
suppressed. main.py wires it to a thin handler that looks up the
printer row and calls the existing _capture_timelapse_baseline_at_start.
Idempotent — skips if a baseline already exists (handles the rare
same-session race where on_print_start also fires for some reason).
The printer doesn't upload the timelapse until after PRINT COMPLETE,
so a baseline captured any time during the print is still pre-upload —
no narrow window to hit.
Verified against the in-the-field logs in #1485 (pwostran's 2026-05-23
support bundle):
pre-reboot: baseline = 7 files
reboot
post-reboot completion: fallback baseline = 8 files (includes new MP4)
-> all 4 retry attempts report "no new files since baseline"
10 new tests cover both the MQTT-side fire decision (fires when
suppressed, doesn't fire when on_print_start handles it, once per
session, payload shape mirrors on_print_start) and the main.py
handler (snapshot capture, double-capture guard, missing-printer-row
guard).