docs: add rel-003, rel-004 releases and update CLI user scoping implementation

Release: REL-003_20260512 — CLI user scoping and local DB ops runbook

Requirements & Batches:
- BAT-003 (REQ-013): portfolio list --user required enforcement with owner filtering
- BAT-004 (REQ-014): portfolio create --user required enforcement with owner assignment
- BAT-007 (REQ-001/002/003): local DB validation runbook and baseline docs update

CLI Enhancements:
- Update user.py: add username-based user lookup (get_by_username)
- Add UserDetailResponse schema with service token listing
- Update list_service_tokens API in user_service.py
- Enhance user detail display with service token information
- Add service_token_count and service_token_names to user responses

Testing:
- Add comprehensive test coverage in test_cli.py for user commands
- Validate username-based lookup functionality

Release: REL-004_20260512 — Portfolio UUID migration and API UUID switch

Requirements & Batches:
- BAT-006 (REQ-016/017/018): portfolio UUID migration complete
- BAT-008 (REQ-019): baseline documentation update for UUID migration

Breaking Changes (REL-003):
- portfolio list requires --user <username> parameter
- portfolio create requires --user <username> parameter

Documentation:
- Create rel-003 and rel-004 release documents with rollout and rollback plans
- Update docs/releases/index.md with new releases
- Update README.md with CLI user scoping clarification
- Sync all release verification checklists and deployment notes

app/services/user_service.py

@@ -6,7 +6,7 @@ from fastapi import Depends
 
 from app.core.config import Settings, get_settings
 from app.core.security import hash_password
-from app.domain.models import User
+from app.domain.models import AuthToken, User
 from app.repositories.factory import get_portfolio_repository_from_settings
 from app.repositories.portfolio_repository import PortfolioRepository
 from app.schemas.user import CreateUserRequest, UpdateUserRequest
@@ -26,6 +26,15 @@ class UserService:
     def get(self, user_id: str) -> User:
         return self._repository.get_user(user_id)
 
+    def get_by_username(self, username: str) -> User:
+        user = self._repository.get_user_by_username(username)
+        if user is None:
+            raise ValueError(f"사용자를 찾을 수 없습니다: {username}")
+        return user
+
+    def list_service_tokens(self, user_id: str, *, include_revoked: bool = True) -> list[AuthToken]:
+        return self._repository.list_service_tokens(user_id, include_revoked=include_revoked)
+
     def create(self, payload: CreateUserRequest) -> User:
         return self._repository.create_user(
             payload.username,