Lets organizers automatically populate a shared Google Sheet (the same kind
they previously built by hand) with an Overview tab and one tab per group,
instead of printing dicts. Group tabs are named after all their members
(not a single host) and show each group's route, course times, and guests
with allergies. The Overview tab also gets configurable Meal Times, Support
Contacts, and Info sections, passed through as plain data from
tatami_masterplan.py. Export is fully opt-in via GOOGLE_SHEETS_CREDENTIALS_FILE
and GOOGLE_SHEETS_SPREADSHEET_ID; without them, behavior is unchanged.
- Add python-dotenv and call load_dotenv() in traveltimes.py before reading
GOOGLE_MAPS_API_KEY (exported env vars still take precedence).
- Add .env.example template; the real .env stays gitignored.
lars