[codex] add Bun and native SQLite providers

[sandrinodm]

Summary

Adds first-class provider support for Node 24+ node:sqlite, Bun bun:sqlite, Bun SQL, optional better-sqlite3, and compatible SQLite clients.

Changes

• Introduces provider adapters and shared transaction handling for synchronous and async SQLite clients.
• Expands the migrator types and tests across Node, Bun, and provider-specific behavior.
• Replaces the single example with provider-specific examples under examples/.
• Moves project tooling from ESLint/Prettier to Biome and adds JSDoc linting.
• Updates CI to validate Node 24/25 and Bun, and updates release publishing to run from GitHub releases with npm provenance.

Validation

• pnpm install --frozen-lockfile
• pnpm typecheck
• pnpm check
• pnpm lint
• pnpm test
• pnpm test:bun
• pnpm build