Same pattern: video_full_cleanup action (scope='video' block + registry), reuses
the shared auto_full_cleanup handler, owned_by='video' system automation on the
music cadence (every 12h). Music copy untouched. Seam tests + EXPECTED_ACTION_NAMES.
Same pattern as phase 2: video_clean_completed_downloads action (scope='video'
block + registry), reuses the shared auto_clean_completed_downloads handler, and
an owned_by='video' system automation on the music cadence (every 5 min). Music
copy untouched. Seam tests for scope isolation, single video-owned seed, and
shared-handler reuse; EXPECTED_ACTION_NAMES updated.
The music side's 'Clean Search History' automation now has a video counterpart so
it appears on the video Automations page too. Distinct action_type
video_clean_search_history (the system seeder keys on action_type, so reusing the
music key would collide), registered to the SAME shared handler so behaviour is
identical, scope='video' block (registry — users can build their own), and an
owned_by='video' system automation on the same 1h cadence. The music action/row
is untouched.
Seam tests: video-scoped only (not on music), music action still music-scoped,
exactly one video-owned system row at the 1h cadence, and it reuses the music
handler. Registration contract (EXPECTED_ACTION_NAMES) updated.
