Add GET /people browse/discover endpoint

Extends the browse/discover pattern already built for movies/series
to the fourth major entity type. No genre/year/status equivalent for
people -- known_for_department is the one categorical filter that
actually means something for a cast/crew list, and sort_by is just
popularity (default) or name. No invalid-filter case either: unlike
genre/status, known_for_department is a plain string compared
directly, nothing to parse or validate.

build_person_summary refactored to share row-to-summary logic with
the new list path, same pattern used for movies/series/companies.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

app/repositories/person_repository.py

@@ -4,12 +4,17 @@ from __future__ import annotations
 
 import uuid
 
-from sqlalchemy import select
+from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.credit import Credit
 from app.models.person import Person
 
+_PERSON_SORT_COLUMNS = {
+    "popularity": Person.popularity,
+    "name": Person.name,
+}
+
 
 async def get_person_by_id(session: AsyncSession, person_id: uuid.UUID) -> Person | None:
     result = await session.execute(select(Person).where(Person.id == person_id))
@@ -24,3 +29,33 @@ async def get_person_credits(session: AsyncSession, person_id: uuid.UUID) -> lis
     )
     result = await session.execute(stmt)
     return list(result.scalars().all())
+
+
+async def list_people(
+    session: AsyncSession,
+    *,
+    known_for_department: str | None,
+    sort_by: str,
+    sort_dir: str,
+    limit: int,
+    offset: int,
+) -> tuple[list[Person], int]:
+    """Browse people with an optional known_for_department filter -- see
+    movie_repository.list_movies for the window-function total-count
+    approach this mirrors. No genre/year/status equivalent for people:
+    department is the one categorical grouping that actually means
+    something when browsing a cast/crew list."""
+
+    column = _PERSON_SORT_COLUMNS[sort_by]
+    order = column.desc() if sort_dir == "desc" else column.asc()
+
+    stmt = select(Person, func.count().over().label("total_count"))
+    if known_for_department is not None:
+        stmt = stmt.where(Person.known_for_department == known_for_department)
+
+    stmt = stmt.order_by(order.nulls_last(), Person.id.asc()).limit(limit).offset(offset)
+
+    rows = (await session.execute(stmt)).all()
+    if not rows:
+        return [], 0
+    return [row[0] for row in rows], rows[0].total_count