pick_barrier.py loops over every tracked DB referenced by the merged
TSV, plots windowed mean inter-fly distance for all 6 ROIs in a single
figure, and lets the analyst click the moment the barrier opens. Saves
to data/metadata/barrier_opening.csv after each pick (crash-safe).
Auto-detector best-effort guess shown as orange dotted line — the
analyst always has the final say.
Output schema:
machine_name, session_date, session_time, opening_s, trim_first_s, notes
`trim_first_s` lets us record misframed starts so downstream code can
ignore the affected window. The 5 2025-07-15 entries are seeded from
the original legacy CSV so they're not re-picked.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>