Podcast USB v0.7.0 — public distribution validation

The 95 regression tests cover feed parsing/filtering, MP3 preservation,
mixed-format joining, concurrent downloads, cancellation, USB presence based on
physical files, title matching and renumbering, transactional USB updates and
recovery, close lifecycle, settings and stage estimates.

Additional checks cover update origins, checksums, ZIP contents, idle installation
coordination, duration title settings and real audio naming after transfer.
The Windows CI job tests copy failure/rollback and runtime/settings preservation.
The UI controller checks automatic download, busy/review/interaction guards,
postponing installation and the restart countdown.

Public-release checks additionally enforce an empty initial lineup and reject
credential-bearing feed URLs in every source/package file. The release package
uses an explicit allowlist and never includes local app data, QA downloads,
settings, caches or paid media. Updating keeps existing Windows user settings.

This application is unsigned. SmartScreen may warn for a new release.
Native desktop appearance and physical work-radio compatibility require a
Windows PC and radio; no such hardware is available in this build environment.
