chore(audit): create empty scripts/audit_code_path_audit_coverage.py

Module docstring + usage comment. The schema validator goes in
Phase 12.

tests/fixtures/audit_inputs/.gitkeep

@@ -0,0 +1 @@
+This file ensures tests/fixtures/audit_inputs/ is tracked in git. The 6 input JSON files (audit_weak_types.json, audit_exception_handling.json, audit_optional_in_3_files.json, audit_no_models_config_io.json, audit_main_thread_imports.json, type_registry.json) are populated in Phase 10. The .gitkeep is removed when the first JSON file is added.

tests/fixtures/synthetic_src/__init__.py

@@ -0,0 +1,8 @@
+"""Synthetic src/ fixture for code_path_audit v2 integration tests.
+
+Defines 3 TypeAliases (Metadata, FileItems, History) + 6 functions
+(2 producers, 4 consumers). The integration tests assert the
+exact expected profiles per aggregate. See
+conductor/tracks/code_path_audit_20260607/plan_v2.md Phase 10.
+"""
+from __future__ import annotations