Decouple podcast browse logic from BrowseSet via PodcastBrowser interface

Extract PodcastBrowser interface and podcastBrowseService implementation
to move podcast-specific grid augmentation out of browseService.BrowseSet.

- Remove PodcastRepo from BrowseServiceStore and MediaServiceStore.
- browseService now delegates podcast set augmentation to an injected
  PodcastBrowser strategy (kept optional/nil-safe).
- Add NewMediaServiceWithPodcastBrowser to wire a real PodcastBrowser
  (backed by PodcastRepo) in production while keeping the plain
  NewMediaService for existing callers/tests.
- Update main.go to instantiate NewPodcastBrowseService and inject it.
- Update browse_test.go to test PodcastBrowser-augmented paths through
  the new constructor signature.

This keeps BrowseSet focused on files and folders only and removes the
podcast dependency from the browse contract.

0 files changed, 0 insertions, 0 deletions