test: migrate Explore controller sessions and ORM models to SQLite

[asukaminato0721]

Summary

• replace mocked SQLAlchemy sessions in Explore audio, completion, message, parameter, saved-message, trial, and workflow controller tests with shared SQLite-backed sessions

• replace App, InstalledApp, AppModelConfig, Workflow, Message, MessageFeedback, Account, Dataset, Tenant, and UploadFile stand-ins with real mapped instances

• persist ownership/resource chains needed by secondary serializer queries while retaining mocks only for external services, DTO/Pydantic responses, pagination, Redis, crypto, and file-provider objects

Real persistence coverage

• callable Flask db.session behavior through scoped sessions backed by sqlite_session_factory
• injected controller sessions through sqlite_session/unbound_session according to ownership
• installed-app to app resolution, workflow/config lookup, message feedback and file queries, tenant/app ownership, and committed model defaults
• missing app/config/workflow behavior through actual database lookups

No production changes.

Size

725 additions + 439 deletions = 1,164 changed lines.

Validation

• make test TARGET_TESTS=./api/tests/unit_tests/controllers/console/explore — 234 passed
• uv run --project . pytest -q --no-cov — 171 passed
• make lint — passed
• make type-check — blocked by mypy 1.20.2 internal error at api/.venv/lib/python3.12/site-packages/mypy/typeshed/stdlib/zipimport.pyi:17
• AST/text audit — no mocked SQLAlchemy sessions/factories and no mapped ORM stand-ins remain in the changed modules

The full test suite was not run, per request.

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	58.89%	58.93%	+0.03%
Strict coverage	58.47%	58.51%	+0.03%
Typed symbols	38,907	38,937	+30
Untyped symbols	27,351	27,333	-18
Modules	3143	3143	0