feat: implement portfolio UUID migration and v1 API finalization (BAT-006, BAT-001 re-verified)

Core Changes:
- Migrate portfolio_id from string to UUID in schema and repository layer
- Update portfolio CLI commands to use name+user combination for identification
- Update HTTP API to accept portfolio_id as UUID path parameter
- Implement portfolio ownership validation in repository queries

Requirements Completed (REQ-016 to REQ-019):
- REQ-016: portfolios table UUID schema migration with data migration script
- REQ-017: CLI portfolio commands with name+user identification
- REQ-018: HTTP API portfolio path parameters and v1 asset_id UUID returns
- REQ-019: Portfolio UUID baseline documentation updates

BAT-001 Re-verification:
- REQ-004~010 marked as Implemented after verification evidence validation
- All v1 API endpoints verified with comprehensive test coverage

Documentation Updates:
- Update data-model.md with portfolio UUID structure
- Update interface-contract.md with UUID path parameters
- Update runtime-flows.md with ownership-based resolution flows
- Update project-structure.md with database layer changes
- Add migration script for portfolio UUID transition

Testing:
- Add test_portfolio_uuid.py for migration validation
- Update test_cli.py and test_portfolio_ownership.py for ownership checks

docs/srs/Interface/req-006_v1-assets-endpoint.md

@@ -1,6 +1,6 @@
 # req-006: GET /v1/assets 엔드포인트 구현
 
-- Status: Approved
+- Status: Implemented
 - Type: Interface
 - Priority: High
 - Owner: repository-maintainers
@@ -39,6 +39,35 @@
 
 ## Change Log
 
+### CHG-20260511-01
+- Date: 2026-05-11
+- Author: repository-maintainers
+
+#### Change Summary
+- Implemented 전환 — BAT-001 re-verified verification passed, confirm-req-implemented 게이트 통과
+
+#### Intent
+- BAT-001 verification.md (re-verified, 2026-05-03, CHG-20260503-01 strategy_type 재검증 포함) AC-1~9 모두 PASS. Blocking Issues 없음.
+
+#### Acceptance Criteria Delta
+- none
+
+#### Impacted Area Delta
+- none
+
+#### Delivery Trace Delta
+- Batches: BAT-001 (release-candidate)
+- Releases: none
+
+#### Revalidation Impact
+- Reverification Needed: no
+- Existing Implementation Invalidated: no
+- Status Recommendation: implemented
+- Follow-up Action: draft-release (BAT-001)
+
+#### Validation Plan
+- BAT-001 verification.md (re-verified) AC-1~9 evidence 연결 확인 완료 (strategy_type 필드 재검증 포함)
+
 ### CHG-20260503-01
 - Date: 2026-05-03
 - Author: repository-maintainers