- add per-request timeout to the Sheets fetch so a hung call can't block /sync
- stop leaking raw sync errors to chat; log detail, reply generically
- migrate logging from log to structured log/slog
- drop duplicate godotenv.Load from ReadSheet (LoadConfig loads .env at startup)
- add multi-stage distroless Dockerfile + .dockerignore; embed tzdata via import
- document single-instance long-polling constraint in README
- translate sheet.go comments to English
- move package doc to doc.go; remove superseded root main.go and live_test.go
Kamil 'Kamaś' Bruchal