chore: release prep 0.2.1 — ship the PATH-less entrypoint

[susheem-k]

Why now

#14 is merged but inert. 0.2.0 is what people install, and it has neither the
__main__.py nor the README guidance:

pyproject.toml:9                          readme = "README.md"   -> README *is* the PyPI page
site-packages/control_plane/__main__.py   -> absent in installed 0.2.0

Everything in #14 exists for someone who has just run pip install and found no
control-plane command. That person gets the PyPI wheel and the PyPI project page —
neither has the fix. Until this ships, #14 helps only people installing from a clone,
who never hit the problem.

Patch, not minor

Purely additive. [project.scripts] is untouched and the console script's output is
byte-identical — prog only differs for the module form, which is new here. No wire,
schema, or API change; the 0.2.x row in the compatibility table already covers this.

Changes

• __version__ and pyproject.toml → 0.2.1
• CHANGELOG.md — [0.2.1] section, fresh empty [Unreleased]
• RELEASING.md — required reviewers on the pypi environment were described as
  optional. They are now configured on all three AgentPlane repos, so the upload pauses
  for approval. Documented, with why it matters: PyPI versions are immutable, so that
  prompt is the last point a bad build can be stopped.

Verification

Checked against the built artifacts, not just the source tree:

check	result
twine check wheel + sdist	PASSED (also confirms the edited README renders on PyPI)
control_plane/__main__.py in wheel	present
entry_points.txt	unchanged — control-plane = control_plane.cli:main
clean venv installed from the wheel	reports 0.2.1; python -m control_plane --help works

Suite: 47 passed. The 3 pre-existing ruff format diffs (remote_store,
store_factory, store_protocol) and the pre-existing ruff check error
(ui/store_client.py:9) are on main already and untouched.

After merge

Actions → Release → Run workflow on main, tag left empty (resolves to v0.2.1).
The run will pause at the PyPI step for environment approval.

🤖 Generated with Claude Code

https://claude.ai/code/session_01EMQxc7WjBTqdUJu18LAskK