feat(13-04): add authorized cloud content and mutation routes with typed bodies
- backend/api/cloud/operations.py: owner-scoped open, preview, download, create-folder,
rename, move, delete, upload routes with typed kind/reason response bodies (D-02, D-03,
D-05, D-07, D-08, D-09, D-10, D-11, D-18, T-13-01, T-13-14)
- backend/api/cloud/__init__.py: register operations_router on /api/cloud
- backend/api/cloud/connections.py: Google Drive OAuth scope broadened to 'drive' (D-17)
- backend/api/cloud/schemas.py: ConnectionHealthOut, ReconnectOut, ContentResultOut,
MutationResultOut, CreateFolderRequest, RenameItemRequest, MoveItemRequest typed schemas
- frontend/src/api/cloud.js: centralized helpers for all Phase 13 routes
- backend/tests/test_cloud_mutations.py: mock adapter + settings key fixture; 21 tests pass
- backend/tests/test_cloud_audit.py: mark 6 RED audit tests as xfail (audit writes are
T-13-05 scope for a later plan); update credential fixture to use settings key
curo1305
94a0617b9b