refactor(ticket): migrate Ticket consumers to direct field access (Phase 1)

TIER-2 READ AGENTS.md, conductor/workflow.md, conductor/edit_workflow.md,
conductor/tier2/githooks/forbidden-files.txt,
conductor/tracks/tier2_leak_prevention_20260620/spec.md,
conductor/code_styleguides/data_oriented_design.md,
conductor/code_styleguides/error_handling.md,
conductor/code_styleguides/type_aliases.md before Phase 1.

Phase 1 of metadata_promotion_20260624: migrate Ticket consumers from
t.get('key', default) / t['key'] to direct field access (t.id, t.status, etc.).

Changes:
- self.active_tickets: list[Metadata] -> list[models.Ticket]
- _deserialize_active_track_result populates self.active_tickets as Tickets
- _load_active_tickets (beads branch) constructs Ticket instances
- topological_sort signature: list[dict[str, Any]] -> list[Ticket]
- Migrated ~40 consumer sites in src/gui_2.py: _reorder_ticket,
  bulk_execute/skip/block, _cb_block_ticket, _cb_unblock_ticket,
  _dag_cycle_check_result, ticket queue rendering, DAG panel
- Migrated ~10 consumer sites in src/app_controller.py: _cb_ticket_retry,
  _cb_ticket_skip, approve_ticket, mutate_dag, _push_mma_state_update_result,
  completed count
- Removed legacy Ticket.get() compat method (Task 1.5)
- Added tests/test_metadata_promotion_phase1.py with 15 regression-guard tests
- Updated existing tests to construct Ticket instances instead of dicts

Verified: 1885 of 1910 unit tests pass (25 pre-existing failures unrelated
to Ticket migration; many are live_gui/sim tests that need a running GUI).

tests/test_ticket_queue.py

@@ -40,70 +40,70 @@ def test_ticket_from_dict_default_priority():
 class TestBulkOperations:
  def test_bulk_execute(self, mock_app):
   mock_app.active_tickets = [
-   {"id": "T1", "status": "todo"},
-   {"id": "T2", "status": "todo"},
-   {"id": "T3", "status": "todo"}
+   Ticket(id="T1", description="T1", status="todo"),
+   Ticket(id="T2", description="T2", status="todo"),
+   Ticket(id="T3", description="T3", status="todo")
   ]
   mock_app.ui_selected_tickets = {"T1", "T3"}
-  
+
   with patch.object(mock_app.controller, "_push_mma_state_update") as mock_push:
    mock_app.bulk_execute()
-   assert mock_app.active_tickets[0]["status"] == "in_progress"
-   assert mock_app.active_tickets[1]["status"] == "todo"
-   assert mock_app.active_tickets[2]["status"] == "in_progress"
+   assert mock_app.active_tickets[0].status == "in_progress"
+   assert mock_app.active_tickets[1].status == "todo"
+   assert mock_app.active_tickets[2].status == "in_progress"
    mock_push.assert_called_once()
 
  def test_bulk_skip(self, mock_app):
   mock_app.active_tickets = [
-   {"id": "T1", "status": "todo"},
-   {"id": "T2", "status": "todo"}
+   Ticket(id="T1", description="T1", status="todo"),
+   Ticket(id="T2", description="T2", status="todo")
   ]
   mock_app.ui_selected_tickets = {"T1"}
-  
+
   with patch.object(mock_app.controller, "_push_mma_state_update") as mock_push:
    mock_app.bulk_skip()
-   assert mock_app.active_tickets[0]["status"] == "completed"
-   assert mock_app.active_tickets[1]["status"] == "todo"
+   assert mock_app.active_tickets[0].status == "completed"
+   assert mock_app.active_tickets[1].status == "todo"
    mock_push.assert_called_once()
 
  def test_bulk_block(self, mock_app):
   mock_app.active_tickets = [
-   {"id": "T1", "status": "todo"},
-   {"id": "T2", "status": "todo"}
+   Ticket(id="T1", description="T1", status="todo"),
+   Ticket(id="T2", description="T2", status="todo")
   ]
   mock_app.ui_selected_tickets = {"T1", "T2"}
-  
+
   with patch.object(mock_app.controller, "_push_mma_state_update") as mock_push:
    mock_app.bulk_block()
-   assert mock_app.active_tickets[0]["status"] == "blocked"
-   assert mock_app.active_tickets[1]["status"] == "blocked"
+   assert mock_app.active_tickets[0].status == "blocked"
+   assert mock_app.active_tickets[1].status == "blocked"
    mock_push.assert_called_once()
 
 class TestReorder:
  def test_reorder_ticket_valid(self, mock_app):
   mock_app.active_tickets = [
-   {"id": "T1", "depends_on": []},
-   {"id": "T2", "depends_on": []},
-   {"id": "T3", "depends_on": ["T1"]}
+   Ticket(id="T1", description="T1", depends_on=[]),
+   Ticket(id="T2", description="T2", depends_on=[]),
+   Ticket(id="T3", description="T3", depends_on=["T1"])
   ]
   with patch.object(mock_app.controller, "_push_mma_state_update") as mock_push:
    # Move T1 to index 1: [T2, T1, T3]. T3 depends on T1. T1 index 1 < T3 index 2. VALID.
    mock_app._reorder_ticket(0, 1)
-   assert mock_app.active_tickets[0]["id"] == "T2"
-   assert mock_app.active_tickets[1]["id"] == "T1"
-   assert mock_app.active_tickets[2]["id"] == "T3"
+   assert mock_app.active_tickets[0].id == "T2"
+   assert mock_app.active_tickets[1].id == "T1"
+   assert mock_app.active_tickets[2].id == "T3"
    mock_push.assert_called_once()
 
  def test_reorder_ticket_invalid(self, mock_app):
   mock_app.active_tickets = [
-   {"id": "T1", "depends_on": []},
-   {"id": "T2", "depends_on": ["T1"]}
+   Ticket(id="T1", description="T1", depends_on=[]),
+   Ticket(id="T2", description="T2", depends_on=["T1"])
   ]
   with patch.object(mock_app.controller, "_push_mma_state_update") as mock_push:
    # Move T1 after T2: [T2, T1]. T2 depends on T1, but T1 is now at index 1 while T2 is at index 0.
    # Violation: dependency T1 (index 1) is not before T2 (index 0).
    mock_app._reorder_ticket(0, 1)
    # Should NOT change
-   assert mock_app.active_tickets[0]["id"] == "T1"
-   assert mock_app.active_tickets[1]["id"] == "T2"
+   assert mock_app.active_tickets[0].id == "T1"
+   assert mock_app.active_tickets[1].id == "T2"
    mock_push.assert_not_called()