feat(REQ-005): implement TrEx Basic V1 API contract with auth, assets, ledger, and user endpoints

- Add V1 API routes for assets, ledger, and user info with complete CRUD operations
- Implement authentication scopes and request validation via auth_routes.py
- Extend schemas with V1-specific models for accounts, holdings, and positions
- Add database queries and aggregations for P&L, performance, and account data
- Include comprehensive test coverage for all V1 endpoints and integration flows
- Update batch and release documentation with implementation and verification evidence
- Sync project structure and runtime flows per V1 API contract requirements

Closes implementation phase of BAT-001 (TrEx Basic V1 API Contract)

tests/test_app.py

@@ -68,6 +68,9 @@ class _BootstrapRepo:
         self.closed = True
 
 
+_TEST_ENC_KEY = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
+
+
 def test_startup_bootstraps_initial_user_when_users_table_empty() -> None:
     repo = _BootstrapRepo()
     settings = Settings(
@@ -76,6 +79,7 @@ def test_startup_bootstraps_initial_user_when_users_table_empty() -> None:
         bootstrap_email="admin@example.com",
         bootstrap_password="bootstrap123",
         allowed_origins_raw="http://localhost:3000",
+        credential_encryption_key=_TEST_ENC_KEY,
     )
     bootstrap_app = create_app(settings_factory=lambda: settings, repository_factory=lambda current: repo)
 
@@ -99,6 +103,7 @@ def test_startup_does_not_bootstrap_when_users_exist() -> None:
         bootstrap_email="admin@example.com",
         bootstrap_password="bootstrap123",
         allowed_origins_raw="http://localhost:3000",
+        credential_encryption_key=_TEST_ENC_KEY,
     )
     bootstrap_app = create_app(settings_factory=lambda: settings, repository_factory=lambda current: repo)