v0.3.0 - Modular Extensions (hbk add)

🧩 Modular extensions system

• New hbk add <module> / hbk add --list — install optional integrations into an existing project, no re-init.
• Modules are declared with a module.json manifest (requirements, env vars, routes, models, repositories, post-install message).
• Project-local registry at .hatchback/modules.json tracks installs for a clean hbk remove <module>.
• hbk remove now auto-detects scaffolded resources vs installed modules.

🐳 Docker is now a module

• Dockerfile, docker-compose.yml, .dockerignore moved to optional_templates/docker/. Still included by default with hbk init; add later with hbk add docker.

💳 Stripe ported to the module system

• hbk init --stripe still works; you can now also run hbk add stripe on any project.

🐛 Fixes

• Edits to requirements.txt / .env now preserve the file's original encoding (UTF-8, UTF-8-BOM, UTF-16). Fixes pip failing with Invalid requirement: 's\x00t\x00r...' after adding a module to PowerShell-generated files.

📚 Docs & tests

• New ROADMAP.md with module catalogue and checkbox tracking.
• README, generated-project README, landing page and hatchback agent skill updated.
• tests/test_modules.py — 7 cases covering install, uninstall round-trip, idempotency, Docker, UTF-16.

Install / upgrade

pip install -U hatchback