Prepare v0.1.0 release

[ecejas]

Why

Give Centaur operators an immutable, copy-paste install target for the first Ambush Streams overlay release.

How

• Pin the documented overlay source and example values to v0.1.0.
• Add a compatibility job that checks out paradigmxyz/centaur read-only.
• Exercise Centaur tool discovery, generated shim startup through uvx, skill installation, SDK placeholder behavior, and the built wheel CLI.

Verification

• uv run --no-project --with pytest --with httpx --with typer --with rich pytest -q (22 passed)
• uvx ruff format --check tests tools
• uvx ruff check tests tools
• actionlint
• Clean venv build/install and tests/centaur_compatibility.py against Centaur 44eb42e1b2fb0fc7fef848ed7e7805e510a10c8e