## Summary

- Harden `plumbus migrate rollback` / `rollbackLastMigration` as
history-only: delete the newest `__drizzle_migrations` row by **id**,
ensure the history table exists first, and return structured
`MigrationRollbackResult` (`status`, `rolledBack`, `tag`, `hash`)
without failing on missing journal/SQL files.
- Make the non-reverting schema behavior explicit in CLI output and
docs; `--json` includes `"schemaReverted": false`.
- Refresh the AI model pricing catalog (2026-08-06): correct
`gpt-5.6-terra` / `gpt-5.6-luna` rates; add specialized OpenAI models
and `claude-opus-5`; track standard-tier / short-context rates only.
- Rewrite the `update-model-pricing` fetch parser for current markdown
pricing pages (tier/section awareness, upcoming Anthropic rates on
stderr) and bump `@plumbus/core` to **0.6.15**.

## Testing

- `packages/plumbus-core/src/data/__tests__/migration.test.ts` —
rollback by id, empty/missing history → `no_migrations`, tag resolution
when files are gone
- `packages/plumbus-core/src/cli/__tests__/migrate.test.ts` — rollback
JSON (`tag`, `schemaReverted: false`), schema warning, empty-history
message
- `packages/plumbus-core/src/ai/__tests__/model-pricing.test.ts` —
gpt-5.6 reduced rates, specialized OpenAI models, `claude-opus-5`
- Full suite (`pnpm lint`, `pnpm format:check`, `pnpm typecheck`, `pnpm
test`): Not run in this change-request draft
- Live `plumbus migrate rollback` against a real DB: Not run