feat!: v0.2.0 — PyPI-ready, interception tests, strict linting

PyPI-ready metadata (donglora-mux), full classifiers, URLs.
Fixed dependency path to client-py. Added 11 interception tests
ported from the Rust mux (SetConfig locking, StartRx/StopRx
refcounting). GitHub Actions CI. Strict ruff linting.

Applied contextlib.suppress per SIM105, collapsed nested ifs per
SIM102.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -1 +1,2 @@
 .venv/
+__pycache__/