feat: add AGENTS.md and Makefile with development guidelines

- Add AGENTS.md with build commands, code style guidelines, and conventional commits
- Add Makefile for common development tasks (build, dev, test, lint, etc.)
- Include git commit guidelines following Conventional Commits specification
- Provide comprehensive development workflow documentation

AGENTS.md

@@ -7,6 +7,12 @@
 - `bun run lint` - Run ESLint on TypeScript files
 - `bun run typecheck` - Run TypeScript type checking without emitting
 
+## Git Commit Guidelines
+Follow Conventional Commits specification: https://www.conventionalcommits.org/en/v1.0.0/
+Format: `<type>[optional scope]: <description>`
+Types: feat, fix, docs, style, refactor, test, chore, perf, ci, build
+Examples: `feat(cli): add session management command`, `fix(db): handle null values in queries`
+
 ## Code Style Guidelines
 - Use TypeScript with strict mode enabled (noImplicitAny: false, strictNullChecks: false)
 - Import style: ES6 imports with `import { X } from './path'` for named exports