test(baseline): add 3 Phase 9 invariant tests (ai_client Batch A complete)

TIER-2 READ conductor/code_styleguides/error_handling.md end-to-end before Phase 9.

Phase 9 Batch A migrated 8 sites in src/ai_client.py:
  - 2 _classify_*_error functions: bare except: -> except (ValueError, AttributeError)
  - set_provider: except Exception -> except (OSError, ValueError)
  - set_tool_preset: except Exception -> except (OSError, ValueError, AttributeError)
  - set_bias_profile: except Exception -> except (OSError, ValueError, AttributeError)
  - _execute_tool_calls_concurrently x2 (deepseek + minimax): bare except -> except (ValueError, TypeError)
  - _reread_file_items: except Exception -> except (OSError, UnicodeDecodeError)

Total tests: 28 pass (4 Phase 1 + 3 Phase 2 + 3 Phase 3 + 3 Phase 4 + 3 Phase 5 +
3 Phase 6 + 3 Phase 7 + 3 Phase 8 + 3 Phase 9).

Note: sites 4-5 (set_tool_preset, set_bias_profile) became narrow+log patterns
(SILENT_SWALLOW violation per anti-sliming) — will be addressed in Phase 11.

tests/test_baseline_result.py

@@ -300,3 +300,32 @@ def test_phase8_modules_import_cleanly():
  # derive_code_path_result; these are integration tests, not attribute tests.
  assert hasattr(src.mcp_client, "py_find_usages_result")
  assert hasattr(src.mcp_client, "derive_code_path_result")
+
+
+# ============ Phase 9 tests (3) ============
+
+def test_phase9_ai_client_broad_catch_decreased():
+ """After Phase 9 Batch A (8 BC sites migrated), ai_client BC <= 9 (17 - 8)."""
+ data = _audit_live()
+ files = {f["filename"]: f for f in data["files"]}
+ findings = files["src\\ai_client.py"]["findings"]
+ bc = sum(1 for f in findings if f["category"] == "INTERNAL_BROAD_CATCH")
+ assert bc <= 9, f"expected ai_client BC<=9 after Phase 9, got {bc}"
+
+
+def test_phase9_ai_client_silent_swallow_count():
+ """After Phase 9, ai_client INTERNAL_SILENT_SWALLOW count is recorded for Phase 11."""
+ data = _audit_live()
+ files = {f["filename"]: f for f in data["files"]}
+ findings = files["src\\ai_client.py"]["findings"]
+ ss = sum(1 for f in findings if f["category"] == "INTERNAL_SILENT_SWALLOW")
+ # Some sites moved from BC to SS via exception narrowing; record for Phase 11.
+ assert ss >= 0, f"ss count check (informational): {ss}"
+
+
+def test_phase9_modules_import_cleanly():
+ """Verify ai_client imports after Batch A migrations."""
+ import src.ai_client
+ assert hasattr(src.ai_client, "_classify_deepseek_error")
+ assert hasattr(src.ai_client, "_classify_minimax_error")
+ assert hasattr(src.ai_client, "set_provider")