feat(plex): the people are local — bios and portraits fetched ahead, not on the click (E30 S6)

A person's TMDB bio was fetched only when their page was first opened, off the request path, so the first
open showed no bio and the page never asked again (2 of 18,202 linked people were ever enriched).

- people_enrich scheduler job (every 10 min, 300 per run): linked people's bios from TMDB and their
  portraits into the image cache, the most-credited people first. A failed TMDB lookup ends the batch.
- Portraits are resized through Plex's photo transcoder to a 320 box (~15 KB instead of ~170 KB; the
  person-image proxy uses the same cache key, and a full-size original is removed as its small twin lands).
- The person response says `enriching` while a bio is on its way (a person the job hasn't reached yet).
- "Known for" is ranked by vote count, without guest visits as themselves (talk shows had crowded out the
  films: Tom Cruise had 14 of 15), with directed works, from a 40-deep pool; the page shows up to 15.
  Migration 0093 un-stamps enriched people so the job refetches them.
- A phased job result (backfill, people_enrich) now counts as a change for the audit trail; before, an
  automatic backfill run that added videos was never audited.
- HU: the watch reconcile job reads "egyeztetés" (a leftover from the S5 sweep).

backend/alembic/versions/0093_plex_person_known_for_votes.py

@@ -0,0 +1,29 @@
+"""re-fetch linked people — "Known for" ranked by votes, without guest visits (E30 S6)
+
+Revision ID: 0093_plex_person_known_for_votes
+Revises: 0092_plex_person_biography_hu
+Create Date: 2026-09-30
+
+A person's "Known for" pool was their credits ranked by TMDB popularity, so talk-show visits as
+themselves crowded out the films (Tom Cruise: 14 of 15 were talk shows, none in the library). The pool is
+now ranked by vote count, without guest visits, with directed works, and deeper. Already-enriched people
+are un-stamped so the people_enrich job fetches them again; their biography stays on the row meanwhile.
+"""
+
+from alembic import op
+
+revision: str = "0093_plex_person_known_for_votes"
+down_revision: str | None = "0092_plex_person_biography_hu"
+branch_labels: str | None = None
+depends_on: str | None = None
+
+
+def upgrade() -> None:
+    op.execute(
+        "UPDATE plex_people SET tmdb_enriched_at = NULL "
+        "WHERE tmdb_person_id IS NOT NULL AND tmdb_enriched_at IS NOT NULL"
+    )
+
+
+def downgrade() -> None:
+    pass  # the watermark only says "fetched"; a refetch under the old ranking is not worth undoing to