Per spec FR3/FR4 + Phase 3.1: the MMA domain dataclasses move to their own module:
- ThinkingSegment, Ticket, Track, WorkerContext, TrackMetadata, TrackState, EMPTY_TRACK_STATE
- TrackMetadata is the renamed (was 'Metadata' dataclass in models.py; renamed to avoid
collision with the Metadata type alias = dict[str, Any])
src/models.py:
- Removed class definitions for ThinkingSegment, Ticket, Track, WorkerContext, Metadata, TrackState, EMPTY_TRACK_STATE
- Added backward-compat re-exports so existing 'from src.models import Ticket' continues to work
- Metadata alias kept for the dataclass name (was confusingly shadowing the type alias)
TrackState's metadata field reverts to the original 'default_factory=dict' pattern
(intentionally not auto-constructing TrackMetadata) to preserve the pre-existing
behavior where accessing state.metadata.id on a missing state.toml throws
AttributeError, which project_manager.get_all_tracks catches and falls through
to metadata.json loading. This was a 'bug-on-purpose' that the test
test_get_all_tracks_with_metadata_json relies on.
Verification: 136 tests pass across mma_models, conductor_engine_v2, dag_engine,
ticket_queue, track_state_schema, thinking_gui, manual_block, pipeline_pause,
phase6_engine, parallel_execution, run_worker_lifecycle_abort, spawn_interception,
persona_id, conductor_engine_abort, conductor_tech_lead, execution_engine,
perf_dag, per_ticket_model, metadata_promotion_phase1, thinking_persistence,
progress_viz, gui_progress, mma_ticket_actions, headless_verification,
context_pruner, orchestration_logic, project_manager_tracks,
track_state_persistence.
