refactor: Phase 1 - rename and simplify backend schemas

backend/src/v1/users/repository.py

@@ -0,0 +1,81 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Protocol
+from uuid import UUID
+
+from sqlalchemy import select
+from sqlalchemy.exc import SQLAlchemyError
+
+from core.db.base_repository import BaseRepository
+from core.logging import get_logger
+from models.profile import Profile
+
+if TYPE_CHECKING:
+    from sqlalchemy.ext.asyncio import AsyncSession
+
+logger = get_logger("v1.users.repository")
+
+
+class UserRepository(Protocol):
+    """Protocol defining the user repository interface."""
+
+    async def get_by_user_id(self, user_id: UUID) -> Profile | None:
+        """Get user by user ID."""
+        ...
+
+    async def get_by_username(self, username: str) -> Profile | None:
+        """Get user by username."""
+        ...
+
+    async def update_by_user_id(
+        self, user_id: UUID, update_data: dict[str, str | None]
+    ) -> Profile | None:
+        """Update user by user ID. Returns updated user or None if not found."""
+        ...
+
+
+class SQLAlchemyUserRepository(BaseRepository[Profile]):
+    """SQLAlchemy implementation of UserRepository.
+
+    Note: This repository only performs CRUD operations.
+    - No commit (only flush) - service layer handles transactions
+    - No auth logic - service layer handles authorization
+    - No HTTP exceptions - returns None or raises SQLAlchemyError
+    """
+
+    def __init__(self, session: AsyncSession) -> None:
+        super().__init__(session, Profile)
+
+    async def get_by_user_id(self, user_id: UUID) -> Profile | None:
+        try:
+            return await self.get_by_id(user_id)
+        except SQLAlchemyError:
+            logger.exception("User lookup failed", user_id=str(user_id))
+            raise
+
+    async def get_by_username(self, username: str) -> Profile | None:
+        try:
+            stmt = (
+                select(Profile)
+                .where(Profile.username == username)
+                .where(Profile.deleted_at.is_(None))
+                .order_by(Profile.created_at.asc())
+                .limit(1)
+            )
+            result = await self._session.execute(stmt)
+            return result.scalar_one_or_none()
+        except SQLAlchemyError:
+            logger.exception("User lookup failed", username=username)
+            raise
+
+    async def update_by_user_id(
+        self, user_id: UUID, update_data: dict[str, str | None]
+    ) -> Profile | None:
+        if not update_data:
+            return await self.get_by_user_id(user_id)
+
+        try:
+            return await self.update_by_id(user_id, update_data)
+        except SQLAlchemyError:
+            logger.exception("User update failed", user_id=str(user_id))
+            raise