feat(plex): search cast & crew names + clickable person cards

Backend (migration 0046_plex_people_search): a new people_text column (cast +
director names, de-duped) is folded into the generated search_vector at weight B,
so the top search box finds titles by an actor/director name and ranks them above
summary-only mentions. New /api/plex/people endpoint returns the cast/crew matching
the term (name prefix or word-start) with a film count + a headshot (pulled from one
representative film's live metadata; image bytes disk-cached).

Frontend: PlexBrowse shows matching people as virtual cards above the grid; clicking
one adds them to the actor/director filter (multi-value, from the C1 work) and clears
the search box so you land on exactly that person's films. Answers the 'why does
"drew" match Rambo?' confusion — it was matching the word in the synopsis; now names
are searchable. i18n en/hu/de.

⚠️ Prod needs a Plex re-sync after deploy to populate people_text (search_vector
regenerates automatically once the column has data).

backend/app/routes/plex.py

@@ -353,6 +353,73 @@ def facets(
     }
 
 
+def _like_escape(s: str) -> str:
+    return s.replace("\\", "\\\\").replace("%", "\\%").replace("_", "\\_")
+
+
+@router.get("/people")
+def people(
+    q: str,
+    library: str,
+    user: User = Depends(current_user),
+    db: Session = Depends(get_db),
+) -> dict:
+    """Cast/crew whose name matches the search term — drives the virtual person cards shown above the
+    grid. Returns up to a few matches (most films first) with a count + a photo."""
+    term = (q or "").strip()
+    lib = db.query(PlexLibrary).filter_by(plex_key=str(library)).first()
+    if lib is None or lib.kind != "movie" or len(term) < 2:
+        return {"people": []}
+    esc = _like_escape(term)
+    pfx, word = f"{esc}%", f"% {esc}%"  # name starts with the term, or any of its words does
+    rows = db.execute(
+        text(
+            "SELECT name, kind, count(*) c FROM ("
+            "  SELECT jsonb_array_elements_text(cast_names) AS name, 'actor' AS kind FROM plex_items"
+            "    WHERE library_id = :lib AND kind = 'movie'"
+            "  UNION ALL"
+            "  SELECT jsonb_array_elements_text(directors) AS name, 'director' AS kind FROM plex_items"
+            "    WHERE library_id = :lib AND kind = 'movie'"
+            ") x WHERE name ILIKE :pfx OR name ILIKE :word "
+            "GROUP BY name, kind ORDER BY c DESC, name LIMIT 5"
+        ),
+        {"lib": lib.id, "pfx": pfx, "word": word},
+    ).all()
+    return {
+        "people": [
+            {"name": name, "kind": kind, "count": c, "photo": _person_photo(db, lib.id, name, kind)}
+            for name, kind, c in rows
+        ]
+    }
+
+
+def _person_photo(db: Session, lib_id: int, name: str, kind: str) -> str | None:
+    """A person's headshot from one representative film's live metadata (image bytes are disk-cached)."""
+    col = PlexItem.directors if kind == "director" else PlexItem.cast_names
+    rk = (
+        db.query(PlexItem.rating_key)
+        .filter(PlexItem.library_id == lib_id, col.contains([name]))
+        .limit(1)
+        .scalar()
+    )
+    if not rk:
+        return None
+    try:
+        with PlexClient(db) as plex:
+            meta = plex.metadata(rk) or {}
+    except (PlexError, PlexNotConfigured):
+        return None
+    for r in meta.get("Director" if kind == "director" else "Role") or []:
+        if r.get("tag") == name:
+            thumb = str(r.get("thumb") or "")
+            return (
+                f"/api/plex/person-image?u={quote(thumb, safe='')}"
+                if thumb.startswith(_PERSON_IMG_HOST)
+                else None
+            )
+    return None
+
+
 @router.get("/show/{rating_key}")
 def show_detail(
     rating_key: str,