@tdd_issue @tdd_issue_554 Feature: TDD Issue #554 — session list DI container missing db provider As a developer I want to verify that `agents session list` fails due to the DI container missing a `db` provider So that the bug is captured and will be caught by a regression test The root cause is that `_get_session_service()` in session.py calls `container.db()`, but the Container class has no `db` provider, causing an AttributeError at runtime. Scenario: Session list command succeeds via DI container Given a CLI runner using the real session DI path When I invoke the session list command Then the session list command should exit successfully Scenario: Session list DI path resolves a SessionService Given a CLI runner using the real session DI path When I request the session service from the DI container Then the session service should be a valid SessionService instance Scenario: Session list command produces structured output via DI Given a CLI runner using the real session DI path When I invoke the session list command with format json Then the session list command should exit successfully And the session list output should be valid JSON