Add GET /companies browse/discover endpoint

Completes the browse/discover set across all four entity types.
Companies have no popularity or date field, so unlike movies/series/
people there's no sort_by choice -- always alphabetical by name.
Filters are company_type (validated against the enum) and country
(a plain ISO 3166-1 code comparison, nothing to validate).

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

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

app/repositories/company_repository.py

@@ -4,10 +4,11 @@ from __future__ import annotations
 
 import uuid
 
-from sqlalchemy import select
+from sqlalchemy import func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.company import Company, MovieCompany, SeriesCompany
+from app.models.enums import CompanyType
 from app.models.movie import Movie
 from app.models.tv import Series
 
@@ -37,3 +38,30 @@ async def get_company_series(session: AsyncSession, company_id: uuid.UUID) -> li
     )
     result = await session.execute(stmt)
     return list(result.scalars().all())
+
+
+async def list_companies(
+    session: AsyncSession,
+    *,
+    company_type: CompanyType | None,
+    country_code: str | None,
+    limit: int,
+    offset: int,
+) -> tuple[list[Company], int]:
+    """Browse companies -- see movie_repository.list_movies for the
+    window-function total-count approach this mirrors. Companies have no
+    popularity/date equivalent to sort by, so this always orders
+    alphabetically by name (with an id tiebreak for stable pagination)."""
+
+    stmt = select(Company, func.count().over().label("total_count"))
+    if company_type is not None:
+        stmt = stmt.where(Company.company_type == company_type)
+    if country_code is not None:
+        stmt = stmt.where(Company.country_code == country_code)
+
+    stmt = stmt.order_by(Company.name.asc(), Company.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