feat(i18n): the person page's biography in Hungarian, from TMDB's translation (E30 S4)

The /person fetch appends translations and keeps TMDB's Hungarian biography beside the instance-language
one (new plex_people.biography_hu, migration 0092). A Hungarian reader is served it, the English one when
TMDB has none. Already-enriched people are un-stamped, so their next open refetches them once.

backend/app/models.py

@@ -1432,6 +1432,10 @@ class PlexPerson(Base, TimestampMixin, UpdatedAtMixin):
     #     no-op fetch so it isn't retried every open). `known_for` = top combined-credits [{tmdb_id,
     #     media_type, title}], resolved to library rows by guid at serve time (like recommendations). ---
     biography: Mapped[str | None] = mapped_column(Text)
+    # TMDB's Hungarian biography (E30 S4), from the same request's `translations`; a Hungarian reader is
+    # served it, and the instance-language `biography` when TMDB has none. Birthplace, aliases and
+    # keywords have no Hungarian on TMDB, so they stay in the instance language.
+    biography_hu: Mapped[str | None] = mapped_column(Text)
     birthday: Mapped[str | None] = mapped_column(String(10))  # "YYYY-MM-DD", served as-is
     deathday: Mapped[str | None] = mapped_column(String(10))
     place_of_birth: Mapped[str | None] = mapped_column(Text)

backend/app/plex/tmdb.py

@@ -132,8 +132,11 @@ class TmdbClient:
         return cast("list[dict] | None", self._get("/configuration/countries"))
 
     def fetch_person(self, person_id: int) -> dict | None:
-        """One person's bio + combined credits (E5 S6), in a single append_to_response request."""
-        return self._get(f"/person/{person_id}", {"append_to_response": "combined_credits"})
+        """One person's bio + combined credits (E5 S6) + the bio's translations (E30 S4), in a single
+        append_to_response request."""
+        return self._get(
+            f"/person/{person_id}", {"append_to_response": "combined_credits,translations"}
+        )
 
 
 def guid_to_tmdb_id(guid: str | None, media_type: str, tmdb: TmdbClient) -> int | None:
@@ -524,6 +527,7 @@ def parse_person(payload: dict) -> dict:
             break
     return {
         "biography": (payload.get("biography") or "").strip() or None,
+        "biography_hu": _translated_bio(payload, "hu"),
         "birthday": payload.get("birthday") or None,
         "deathday": payload.get("deathday") or None,
         "place_of_birth": payload.get("place_of_birth") or None,
@@ -533,8 +537,17 @@ def parse_person(payload: dict) -> dict:
     }
 
 
+def _translated_bio(payload: dict, lang: str) -> str | None:
+    """The `lang` biography from the appended `translations` (TMDB leaves an untranslated one blank)."""
+    for tr in (payload.get("translations") or {}).get("translations") or []:
+        if tr.get("iso_639_1") == lang:
+            return ((tr.get("data") or {}).get("biography") or "").strip() or None
+    return None
+
+
 def apply_person(row: PlexPerson, parsed: dict) -> None:
     row.biography = parsed["biography"]
+    row.biography_hu = parsed["biography_hu"]
     row.birthday = parsed["birthday"]
     row.deathday = parsed["deathday"]
     row.place_of_birth = parsed["place_of_birth"]

backend/app/routes/plex/people.py

@@ -243,7 +243,10 @@ def person_detail(
     return {
         "name": name,
         "photo": person.photo_thumb if person else None,
-        "biography": person.biography if person else None,
+        # The Hungarian biography for a Hungarian reader, the instance-language one when TMDB has none.
+        "biography": ((person.biography_hu if lang == "hu" else None) or person.biography)
+        if person
+        else None,
         "birthday": person.birthday if person else None,
         "deathday": person.deathday if person else None,
         "place_of_birth": person.place_of_birth if person else None,