Initial commit: Backend with Bun.serve() + Drizzle ORM

- Bun 1.3.6 server setup
- MariaDB schema (projects, agents, tasks)
- Auto-migrations on startup
- WebSocket support
- Health check endpoint

Co-Authored-By: Claude Sonnet 4.5 (1M context) <noreply@anthropic.com>

.cursor/rules/use-bun-instead-of-node-vite-npm-pnpm.mdc

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+../../CLAUDE.md