fix: make Windows tool output decoding explicit

[guantw]

Changes

• Parse localized Windows netstat output as raw bytes so Python UTF-8 mode cannot break HDC listener detection.
• Decode every HDC command as UTF-8 with replacement, including server lifecycle, UDID lookup, target listing, bundle inspection, and installation.
• Raise an explicit, argument-safe process output error when captured output is undecodable or unexpectedly None, and discard localized taskkill output that is not consumed.
• Add regression coverage and document the fix in the changelog.

Validation

• python -m ruff format --check .
• python -m ruff check .
• python -m pytest --cov — unavailable because the existing editable-install environment does not contain the declared pytest-cov development dependency.
• python -m pytest -q — 297 passed, 2 skipped.
• PYTHONUTF8=1 PYTHONIOENCODING=utf-8 python -m pytest -q — 297 passed, 2 skipped, with no subprocess reader warnings.
• New and repaired logic has account- and device-independent regression tests.
• User-visible behavior is documented in CHANGELOG.md.
• No token, certificate, private key, UDID, HAP, log, or machine configuration is committed.
• No dependencies were added.
• Portable packaging checks are not applicable.

Manual testing

On an authorized connected device, Installer.get_udid() returned a valid 64-character value both with Python's default encoding mode and with PYTHONUTF8=1. The value was not logged. Signing, deployment, and installation were not performed.