[chore] remove all remaining type:ignore suppressions from tests/

Converts 115 `# type: ignore[...]` suppressions across 23 test files to
no-suppression patterns (helper-return widening to Any, local Any aliases,
cc:Any aliases, cast at narrow call sites, typed fixtures) so the hard
no-type:ignore convention holds across tests/. No test logic or assertions
changed — only mock-wiring mechanics and type annotations.

Gate: ruff check tests/ clean; mypy tests/ (538 files) clean; 176 changed-file
tests pass. Zero real suppressions remain (the 7 grep hits are 3 hygiene-
checker string-literal test inputs and 4 prose mentions in comments).

tests/unit/models/test_misc_models.py

@@ -7,6 +7,7 @@ properties, factory functions, lookup helpers, and __post_init__ branches.
 from __future__ import annotations
 
 from pathlib import Path
+from typing import Any, cast
 from unittest.mock import patch
 from uuid import uuid4
 
@@ -65,7 +66,8 @@ def test_agent_instance_post_init_assigns_uuid_when_falsy() -> None:
     # Forcing an empty UUID(int=0) is falsy → the post_init triggers re-assign.
     inst = AgentInstance.__new__(AgentInstance)
     # Fill required dataclass fields explicitly so __post_init__ runs cleanly.
-    inst.id = None  # type: ignore[assignment]
+    cc: Any = inst
+    cc.id = None
     inst.agent_id = "be-dev-1"
     inst.state = OrchestratorAgentState.OFFLINE
     inst.container_id = None
@@ -185,7 +187,7 @@ def test_a2a_state_to_task_status_unknown_returns_pending() -> None:
         pass
 
     fake = _FakeState()
-    assert a2a_state_to_task_status(fake) == "pending"  # type: ignore[arg-type]
+    assert a2a_state_to_task_status(cast("Any", fake)) == "pending"
 
 
 def test_a2a_state_to_task_status_known() -> None: