Every Store method now returns an error. Callers handle errors
gracefully — TUI logs to event log, server returns HTTP 500,
monitor engine logs and retries. All rows.Scan() errors are now
checked in sqlstore.go instead of silently appending corrupt data.
- GetSites, GetAllAlerts, GetAllUsers return ([]T, error)
- GetAlert returns (AlertConfig, error) instead of (AlertConfig, bool)
- AddSite, UpdateSite, DeleteSite, etc. all return error
- SaveCheck, LoadAllHistory, ExportData return error
- ~25 caller sites updated across tui, server, monitor, main
Extract shared SQLStore with Dialect interface for the ~5% that
differs between backends (DDL, placeholders, sequence resets).
- New dialect.go: Dialect interface + placeholder rewriter (? → $N)
- New sqlstore.go: single implementation of all 19 Store methods
- sqlite.go: reduced from 286 to 83 lines (SQLiteDialect only)
- postgres.go: reduced from 266 to 78 lines (PostgresDialect only)
- main.go: use NewSQLiteStore/NewPostgresStore constructors
Zero CRUD logic duplication. Every future schema change written once.