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/alembic/versions/0092_plex_person_biography_hu.py

@@ -0,0 +1,31 @@
+"""add biography_hu to plex_people — TMDB's Hungarian biography (E30 S4)
+
+Revision ID: 0092_plex_person_biography_hu
+Revises: 0091_plex_tagline_hu
+Create Date: 2026-09-29
+
+The person page showed a Hungarian reader the English biography although TMDB has a Hungarian one for
+most people. The person fetch now appends `translations` and keeps the Hungarian biography beside the
+English one. Already-enriched people are un-stamped, so their next page open refetches them once (the
+same lazy path as a first open) and fills it; until then the English biography stands in.
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0092_plex_person_biography_hu"
+down_revision: str | None = "0091_plex_tagline_hu"
+branch_labels: str | None = None
+depends_on: str | None = None
+
+
+def upgrade() -> None:
+    op.add_column("plex_people", sa.Column("biography_hu", sa.Text(), nullable=True))
+    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:
+    op.drop_column("plex_people", "biography_hu")

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,

backend/tests/test_plex_person_bio.py

@@ -332,3 +332,74 @@ def test_person_detail_serves_bio_and_resolves_known_for(db, monkeypatch, overri
     assert j["also_known_as"] == ["Alt Name"]
     # Only the in-library known_for credit resolves to a card; the out-of-library one is dropped.
     assert [c["title"] for c in j["known_for"]] == ["Known Movie"]
+
+
+# --- E30 S4: the biography in the reader's language --------------------------------------------------
+# The same /person request appends `translations`; the Hungarian one is kept beside the instance-language
+# biography, and a Hungarian reader is served it, falling back to the English one when TMDB has none.
+
+
+def _translation(lang: str, bio: str) -> dict:
+    return {"iso_639_1": lang, "iso_3166_1": lang.upper(), "data": {"biography": bio}}
+
+
+def test_parse_person_keeps_the_hungarian_biography():
+    payload = {
+        **PAYLOAD,
+        "translations": {
+            "translations": [
+                _translation("de", "Ein Schauspieler."),
+                _translation("hu", "  Ünnepelt színész.  "),
+            ]
+        },
+    }
+    assert plex_tmdb.parse_person(payload)["biography_hu"] == "Ünnepelt színész."
+
+
+def test_parse_person_without_a_hungarian_biography():
+    assert plex_tmdb.parse_person(PAYLOAD)["biography_hu"] is None
+    blank = {**PAYLOAD, "translations": {"translations": [_translation("hu", "   ")]}}
+    assert plex_tmdb.parse_person(blank)["biography_hu"] is None
+
+
+def test_fetch_person_asks_for_the_translations():
+    client = plex_tmdb.TmdbClient.__new__(plex_tmdb.TmdbClient)
+    seen: list[dict] = []
+    client._get = lambda path, params=None: seen.append(params or {}) or {}  # type: ignore[method-assign]
+    client.fetch_person(500)
+    assert "translations" in seen[0]["append_to_response"].split(",")
+
+
+def test_person_detail_serves_the_biography_in_the_readers_language(db, monkeypatch, override_dep):
+    from datetime import datetime, timezone
+
+    done = datetime(2024, 1, 1, tzinfo=timezone.utc)
+    db.add(PlexLibrary(plex_key="7", title="Movies", kind="movie", enabled=True))
+    db.add_all(
+        [
+            PlexPerson(
+                name="Both P",
+                tmdb_person_id=1,
+                tmdb_enriched_at=done,
+                biography="English bio.",
+                biography_hu="Magyar életrajz.",
+            ),
+            PlexPerson(
+                name="Only EN P", tmdb_person_id=2, tmdb_enriched_at=done, biography="Only English."
+            ),
+        ]
+    )
+    user = User(email="biolang@example.com")
+    db.add(user)
+    db.commit()
+
+    def bio(name: str, lang: str) -> str | None:
+        resp = _get(db, user, monkeypatch, override_dep, f"/api/plex/person/{name}?lang={lang}")
+        assert resp.status_code == 200, resp.text
+        return resp.json()["biography"]
+
+    assert bio("Both P", "hu") == "Magyar életrajz."
+    assert bio("Both P", "en") == "English bio."
+    assert (
+        bio("Only EN P", "hu") == "Only English."
+    )  # TMDB has no Hungarian one: the English stands in