Migrate Sheets auth from an API key to a service-account credential
(GOOGLE_CREDENTIALS_FILE) with the read+write spreadsheets scope, add a
WriteSheet primitive, and use it to actively manage empty duty weeks in
the weekly reminder.
Each fire now handles a fixed this-week/next-week model (replacing the
DUTY_AHEAD_DAYS announce):
- this week empty -> pick the two people with the fewest duties (random
tie-break), write their names into cols B/C, and announce
- this week filled -> announce who is on duty
- next week empty -> ask people to volunteer before it is auto-assigned
Col G ("Liczba dyżurów") is a live formula, so names-only writes keep the
fewest-duties selection fair across weeks. Selection, row tracking, range
building, and every fire() branch are unit-tested; live tests for sheet
read/write are env-gated.
LoadConfig read SPREADSHEET_ID, but the .env defines GOOGLE_SHEETS_ID,
so config loading failed. The default SHEET_RANGE was also a hardcoded
'Dyżury!A1:F100', but the spreadsheet tabs are named per year (e.g.
'2026'), producing a 400 'Unable to parse range'. Read GOOGLE_SHEETS_ID
and derive the default range from the current year.
Add a RUN_LIVE-gated integration test that drives the full
LoadConfig -> Service -> Syncer.Sync -> Store path against the live
Sheet, and gitignore the generated rota.json cache.