v0.1.1 — acp-client skill and doc cleanup

Since v0.1.0: new acp-client skill (session protocol for coordinating agents, in skills/ with its .claude install copy and lockfile); removed the stale port-volatility section from the skill; trimmed the mwg-pixel-dungeon paragraph from the server docstring. No behavior changes. Verified with smoke_test.py and test_store.py. Loopback only, no auth — do not expose the port.