v0.2.1 — drop Python 3.9 (mcp transitive requires 3.10+)

[0.2.1] - 2026-05-16

Fixed

• Drop Python 3.9 support. The mcp runtime dependency (introduced for the
  dvr mcp server in v0.2.0) requires Python 3.10+, so pipx install on a 3.9
  interpreter failed with No matching distribution found for mcp>=1.0.
  requires-python is now >=3.10; classifiers, ruff target, and the CI
  matrix have been aligned. v0.2.0 has been yanked from PyPI.
• Cross-platform test fixtures: FakeMediaPool.ImportMedia /
  FakeProjectManager.ImportProject and tests/unit/test_bootstrap_cross_platform.py
  no longer assume POSIX path separators, fixing 5 spurious Windows-only CI
  failures. Production code unchanged.