Enhance CLAUDE guidelines and agent linkage

[PeterDaveHello]

Detail Go formatting and race-safe test expectations for backend work.

List frontend linting commands so CLAUDE matches current workflows.

Link AGENTS.md to CLAUDE.md so other agents reuse the strengthened guide.

GitHub Copilot summary:

This pull request adds a new documentation file and updates the development guidelines and commands to emphasize code quality, formatting, and testing standards for both backend and frontend development.

Documentation updates:

• Added the CLAUDE.md file to the project documentation.

Backend development standards:

• Updated guidelines to require running gofmt/goimports for code formatting and validating changes with go test ./... -race -cover before pushing.
• Enhanced backend commands to include go generate ./... and more detailed instructions for building and testing, including release artifact generation.

Frontend development standards:

• Added instructions to run pnpm lint, pnpm lint:fix, and pnpm typecheck to maintain style and type consistency.
• Updated frontend commands to include linting and type checking as part of the development workflow.

Development environment:

• Added instructions for bootstrapping a demo stack using Docker Compose.

[0xJacky]

Thanks