feat: initial p2pkg tool with CI, ruff, and stable tagging

https://chatgpt.com/share/69468609-0584-800f-a3e0-9d58210fb0e8

README.md

@@ -1,6 +1,61 @@
 # p2pkg
 
-Homepage: https://git.veen.world/kevinveenbirkenbach/p2pkg
+A small, purpose-built repository for a very specific migration:
 
-## Author
-Kevin Veen-Birkenbach <kevin@veen.world>
+- `foo.py` ➜ `foo/__main__.py`
+- Generates `foo/__init__.py` that re-exports the public API from `__main__`
+  so existing code like `import foo` or `from foo import some_function` keeps working.
+- Keeps the original module code *as-is* in `__main__.py` (one-off refactor helper).
+
+## Install (editable)
+
+```bash
+python -m venv .venv
+. .venv/bin/activate
+pip install -e .
+```
+
+## Usage
+
+```bash
+# Migrate one or more flat modules into packages
+p2pkg roles_list.py another_module.py
+
+# Or run directly
+python tools/p2pkg.py roles_list.py
+```
+
+### Behavior
+
+Given `roles_list.py`:
+
+```
+roles_list.py
+```
+
+After migration:
+
+```
+roles_list/
+├── __init__.py      # re-exports public API from __main__
+└── __main__.py      # contains the original implementation (moved)
+```
+
+- Running `python -m roles_list` executes `roles_list/__main__.py`.
+- Existing imports remain compatible (via re-exports in `__init__.py`).
+
+## Development
+
+Run tests:
+
+```bash
+make test
+```
+
+## License
+
+MIT License. See `LICENSE`.
+
+---
+
+Author: Kevin Veen-Birkenbach