Document the noxfile improvement that extends the pre-migrated SQLite
template database to slow_integration_tests and e2e_tests sessions,
eliminating redundant Alembic migrations across all test suites.
ISSUES CLOSED: #2334
Document the new DomainBaseModel base class introduced in PR #1941.
Adds a dedicated section at the top of docs/api/core.md covering the
class signature, model_config semantics table, and a usage example.
ISSUES CLOSED: #1941