fix(console): persist early worker failures in session history

[Iams4kura]

Summary

• Fixes Worker that exits before start_session leaves no session row, so the failure is never persisted or surfaced #124.
• Symptom: A worker that exits before DataEngine.start_session leaves no SQLite session row; /api/sessions cannot show its failed status.
• Root cause: The queue fallback calls UPDATE sessions WHERE session_id, but start_session has not inserted that row. A zero-row update returns false and the failure is only logged.
• The fallback now inserts a terminal row with the queued goal and start time. Existing rows keep their other fields.

Regression evidence

• Before: uv run pytest tests/unit/admin_console/test_task_queue_service.py::test_worker_failure_before_session_start_is_visible_in_session_history -q exited 1

• After: uv run pytest tests/unit/admin_console/test_task_queue_service.py::test_worker_failure_before_session_start_is_visible_in_session_history -q exited 0

Verification

• uv run pytest tests/unit/admin_console/ -q
• uv run ruff check apps/admin_console/database/repositories/session_repository.py apps/admin_console/services/task_queue_service.py tests/unit/admin_console/test_task_queue_service.py
• uv run ruff format --check apps/admin_console/database/repositories/session_repository.py apps/admin_console/services/task_queue_service.py tests/unit/admin_console/test_task_queue_service.py
• uv run python scripts/quality_ratchet.py
• make typecheck

Scope

• 3 files changed, +87 / -4 lines

Existing full-suite limitations

• make test on macOS with Python 3.12: 2,104 passed, 10 skipped, 82 failed outside the changed admin console area. Three representative failures (missing Google key, invalid mock provider, Windows-only emulator assertion) also fail on the untouched base commit.
• make lint: 11 Ruff findings in untouched playground/backend_manager files; the same findings occur on the untouched base. The three changed files pass Ruff format and lint checks.