refactor(consumers): replace 'models.<moved_class>' with direct imports

Per post_module_taxonomy_de_cruft_20260627 Phase 2 (FR7 continued).
The previous migration commit (8f11340b) handled the
'from src.models import X' pattern (85 sites). This commit handles
the 'models.<moved_class>' attribute access pattern (44 sites in 20
files), which the __getattr__ shim previously supported.

The migration was performed by the one-time script
scripts/tier2/artifacts/post_module_taxonomy_de_cruft_20260627/migrate_models_attr.py
which:
 1. For each 'models.<moved_class>' reference, replaces it with the
    bare class name (e.g., 'models.MCPConfiguration' -> 'MCPConfiguration')
 2. Adds the import 'from src.<destination> import <moved_class>' at
    the top of the file (deduplicated if the import already exists)
 3. Skips moved classes that the file already imports directly

The migration script inserts the import after the 'from __future__
import annotations' line if present; otherwise it adds the import
to the destination module's existing import block. Two files
required manual fixes because the script's regex didn't handle them:
 - src/rag_engine.py: uses 'from src import models' (not 'from
                            src.models import X'); the class is accessed
                            via 'models.RAGConfig'. Replaced with a
                            direct 'from src.mcp_client import RAGConfig'
                            import and removed the 'from src import models'.
 - tests/test_project_context_20260627.py: uses the parens-style
                            multi-line 'from src.models import (X, Y, Z)'.
                            Replaced with the parens-style direct import.

After this commit:
 - 'models.MCPConfiguration', 'models.FileItem', 'models.Ticket', etc.
   no longer work in src/ and tests/ (the AttributeError raises
   because models.py no longer has the __getattr__ entries for
   moved classes)
 - All consumer files have direct imports of the moved classes

Total: 44 'models.<moved_class>' references rewritten across 20 files.

tests/test_metadata_promotion_phase1.py

@@ -2,8 +2,8 @@
 Phase 1 of metadata_promotion_20260624.
 
 Verifies:
- 1. self.active_tickets load boundaries convert dicts to models.Ticket
- 2. conductor_tech_lead.topological_sort returns list[models.Ticket]
+ 1. self.active_tickets load boundaries convert dicts to Ticket
+ 2. conductor_tech_lead.topological_sort returns list[Ticket]
  3. gui_2.py consumer sites use direct field access (not .get())
  4. app_controller.py consumer sites use direct field access (not .get())
 """
@@ -15,11 +15,11 @@ from src.mma import Ticket
 
 class TestActiveTicketsType:
  def test_active_tickets_annotation_is_list_of_ticket(self) -> None:
-  """self.active_tickets type hint must be list[models.Ticket], not list[Metadata]."""
+  """self.active_tickets type hint must be list[Ticket], not list[Metadata]."""
   from src.app_controller import AppController
   src_text = inspect.getsource(AppController.__init__)
-  assert "list[models.Ticket]" in src_text, (
-   "AppController.__init__ must declare self.active_tickets: list[models.Ticket]"
+  assert "list[Ticket]" in src_text, (
+   "AppController.__init__ must declare self.active_tickets: list[Ticket]"
   )
   assert "list[Metadata]" not in src_text.split("self.active_tickets")[1].split("\n")[0], (
    "AppController.__init__ must NOT declare self.active_tickets: list[Metadata]"
@@ -28,7 +28,7 @@ class TestActiveTicketsType:
 
 class TestActiveTicketsLoadBoundaries:
  def test_load_at_data_converts_dicts_to_tickets(self) -> None:
-  """_deserialize_active_track_result boundary must wrap dicts as models.Ticket."""
+  """_deserialize_active_track_result boundary must wrap dicts as Ticket."""
   from src.app_controller import AppController
   with patch.object(AppController, "load_config", return_value={
    'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'},
@@ -56,7 +56,7 @@ class TestActiveTicketsLoadBoundaries:
     )
 
  def test_load_active_tickets_beads_branch_converts_dicts_to_tickets(self) -> None:
-  """_load_active_tickets (beads branch) must wrap bead dicts as models.Ticket."""
+  """_load_active_tickets (beads branch) must wrap bead dicts as Ticket."""
   from src.app_controller import AppController
   from src.mma import Ticket
   ctrl = AppController.__new__(AppController)
@@ -79,7 +79,7 @@ class TestActiveTicketsLoadBoundaries:
 
 class TestTopologicalSortReturnsTicketList:
  def test_topological_sort_returns_ticket_instances(self) -> None:
-  """conductor_tech_lead.topological_sort must return list[models.Ticket]."""
+  """conductor_tech_lead.topological_sort must return list[Ticket]."""
   from src import conductor_tech_lead
   sig = inspect.signature(conductor_tech_lead.topological_sort)
   assert sig.return_annotation is not inspect.Signature.empty