fix: move test artifacts to tmp directory and update gitignore

- Create tmp/test_artifacts/ directory for test storage
- Add tmp/ to .gitignore to exclude test artifacts from version control
- Update test files to use project tmp directory instead of system temp
- Add test-specific path constants for consistent configuration
- Prevent asset_registry.json from being overwritten by tests

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/test_issue_146_final_integration.py

@@ -45,7 +45,10 @@ class TestFinalAssetManagementIntegration:
     @pytest.fixture
     def integration_workspace(self):
         """Create a comprehensive test workspace with realistic data."""
-        temp_dir = Path(tempfile.mkdtemp(prefix="asset_integration_"))
+        # Use project tmp directory instead of system temp
+        project_root = Path(__file__).parent.parent
+        temp_dir = project_root / "tmp" / "test_artifacts" / f"integration_{int(time.time())}"
+        temp_dir.mkdir(parents=True, exist_ok=True)
 
         # Create realistic project structure
         project_dir = temp_dir / "test_project"
@@ -92,7 +95,11 @@ Content for comprehensive testing of the asset management system.
     def asset_manager(self, integration_workspace):
         """Initialize AssetManager for integration testing."""
         storage_path = integration_workspace / "asset_storage"
-        manager = AssetManager(storage_path=storage_path)
+        registry_path = integration_workspace / "test_registry.json"
+        manager = AssetManager(
+            storage_path=storage_path,
+            registry_path=registry_path
+        )
         return manager
 
     def test_complete_ecosystem_initialization(self, integration_workspace):
@@ -505,7 +512,10 @@ class TestAssetManagementPerformanceBenchmarks:
     @pytest.fixture
     def benchmark_workspace(self):
         """Create large-scale test workspace for benchmarking."""
-        temp_dir = Path(tempfile.mkdtemp(prefix="asset_benchmark_"))
+        # Use project tmp directory instead of system temp
+        project_root = Path(__file__).parent.parent
+        temp_dir = project_root / "tmp" / "test_artifacts" / f"benchmark_{int(time.time())}"
+        temp_dir.mkdir(parents=True, exist_ok=True)
 
         # Create variety of file types and sizes
         file_types = [