Storage: schema migrations & versioning (embed migrations)

[thenotespublisher]

Impact: Hard to evolve schema safely; upgrade/downgrade risks for users.
No dedicated migration tool or embedded migrations visible.

i recommend

Add embedded migrations (use golang-migrate or pressly/goose) and run on startup with explicit migrate apply.

Store schema version in DB and fail fast if incompatible.
Snippet:
migrate -path ./migrations -database "sqlite3://path" up

[steipete]

Landed on main.\n\nStorage now uses explicit schema versioning with :\n- stamp baseline schema version during migration\n- fail fast when local DB schema is newer than supported binary\n- add regression tests for schema stamp/backfill/future-version failure\n\nCommit: 86b4c47

[steipete]

Follow-up note: schema versioning is implemented via PRAGMA user_version (commit 86b4c47).