#282 chore: release v1.2.1

Summary

• Release the pending patch Changesets as sql-fs-api 1.2.1.
• Update the package, OpenAPI, and README versions, and add the generated changelog entry.
• Include the security dependency updates from PR #275 in the release notes.

Verification

• pnpm check:architecture and pnpm check:scripts passed.
• 2,359 core/API tests, 154 TypeScript SDK tests, and 174 Python tests passed.
• Build and high-severity dependency audit passed.
• Biome, TypeScript checks, and Oxlint passed with the untracked scripts/loadtest/ directory excluded. Full pnpm check reports three existing Oxlint findings in that untracked directory.