LATTICE Schema Migration Authoring

To keep Pixeltable schema migrations in sync with documentation, author new migrations using helper functions and simultaneously update `meta/SCHEMA.md` and `meta/ARCHITECTURE.md` to reflect the changes before running pre-commit checks.

Adding a table in a `lattice/*` namespace without causing docs drift requires creating a new write-once numbered migration file, updating `_helpers.py` ownership, and running the schema scoring ratchet to validate documentation consistency.

You cannot modify existing Pixeltable migrations because migrations 0001–0014 are immutable and write-once. You must author a new numbered migration file, such as 0015 or higher, to implement any schema changes safely.

Your schema score fails when adding new columns because the canonical documentation has drifted from the runtime schema. You must update `meta/SCHEMA.md` and architecture state, then run `scripts/score-schema.sh` to validate the changes.

You need to update `_helpers.py` when creating a new `lattice/*` namespace to enforce ownership rules and ensure idempotent schema changes, which prevents forbidden geometry writes and maintains schema integrity.

Write-once migration discipline prevents schema inconsistencies by enforcing immutable historical migrations and requiring all new schema changes to be authored through helper-only functions, ensuring runtime schemas remain consistent with canonical documentation.