feat: implement OrganizationRepository with CRUD operations

app/repositories/org_repo.py

@@ -0,0 +1,49 @@
+"""Organization repository for database operations."""
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.organization import Organization, OrganizationCreate
+from app.models.organization_member import OrganizationMember
+
+
+class OrganizationRepository:
+    """Provides CRUD helpers for Organization model."""
+
+    def __init__(self, session: AsyncSession) -> None:
+        self._session = session
+
+    @property
+    def session(self) -> AsyncSession:
+        return self._session
+
+    async def list(self) -> Sequence[Organization]:
+        result = await self._session.scalars(select(Organization))
+        return result.all()
+
+    async def get_by_id(self, organization_id: int) -> Organization | None:
+        return await self._session.get(Organization, organization_id)
+
+    async def get_by_name(self, name: str) -> Organization | None:
+        stmt = select(Organization).where(Organization.name == name)
+        result = await self._session.scalars(stmt)
+        return result.first()
+
+    async def list_for_user(self, user_id: int) -> Sequence[Organization]:
+        stmt = (
+            select(Organization)
+            .join(OrganizationMember, OrganizationMember.organization_id == Organization.id)
+            .where(OrganizationMember.user_id == user_id)
+            .order_by(Organization.id)
+        )
+        result = await self._session.scalars(stmt)
+        return result.unique().all()
+
+    async def create(self, data: OrganizationCreate) -> Organization:
+        organization = Organization(name=data.name)
+        self._session.add(organization)
+        await self._session.flush()
+        return organization