Add initial devcell setup and tooling configuration

[DimmKirr]

Changes

• chore(pyproject.toml): add Python project metadata and dependencies for devcontainer tools
• chore(.pre-commit-config.yaml): add gitleaks hook for secret detection in PRs
• chore(.github/workflows/pr.yml): configure GitHub Actions for PR checks including secret scanning and build/test steps
• chore(entrypoint.sh): add entrypoint script to start Xvfb, fluxbox, and x11vnc for GUI support in container
• chore(.gitignore): add typical ignores including virtualenvs, node_modules, and local compose override files
• chore(package.json): initialize npm project with devcontainer-related tools and postinstall script
• chore(.env-example): provide example environment variables for git author and API keys
• chore(uv.lock): add Python dependency lock file with pinned packages for devcontainer environment
• chore(Taskfile.yml): add taskfile for running Claude CLI inside devcontainer with deploy task and shell access
• chore(README.md): add detailed documentation for devcontainer, usage instructions, features, and customization guidelines
• chore(.tool-versions-example): add example asdf version manager config for various tools and languages
• chore(compose.yml): add Docker Compose config for devcontainer service with volumes, env, ports, and network setup
• chore(package-lock.json): add npm lockfile with resolved dependencies matching package.json
• chore(Vagrantfile): add Vagrant config for macOS VM with ssh, synced folders, and provisioning for asdf installation
• chore(compose.local-example.yml): add example local override file for docker-compose with customizable mounts and env vars