● feat: Draft pip package policy management system (not yet integrated)

Add comprehensive pip dependency conflict resolution framework as draft implementation. This is self-contained and does not affect existing
ComfyUI Manager functionality.

Key components:
- pip_util.py with PipBatch class for policy-driven package management
- Lazy-loaded policy system supporting base + user overrides
- Multi-stage policy execution (uninstall → apply_first_match → apply_all_matches → restore)
- Conditional policies based on platform, installed packages, and ComfyUI version
- Comprehensive test suite covering edge cases, workflows, and platform scenarios
- Design and implementation documentation

Policy capabilities (draft):
- Package replacement (e.g., PIL → Pillow, opencv-python → opencv-contrib-python)
- Version pinning to prevent dependency conflicts
- Dependency protection during installations
- Platform-specific handling (Linux/Windows, GPU detection)
- Pre-removal and post-restoration workflows

Testing infrastructure:
- Pytest-based test suite with isolated environments
- Dependency analysis tools for conflict detection
- Coverage for policy priority, edge cases, and environment recovery

Status: Draft implementation complete, integration with manager workflows pending.

tests/pytest.ini

@@ -0,0 +1,41 @@
+[pytest]
+# Global pytest configuration for comfyui-manager tests
+
+# Test discovery
+python_files = test_*.py
+python_classes = Test*
+python_functions = test_*
+
+# Add comfyui_manager to Python path
+pythonpath = ../comfyui_manager
+
+# Output options
+addopts =
+    # Verbose output
+    -v
+    # Show extra test summary info
+    -ra
+    # Show local variables in tracebacks
+    --showlocals
+    # Strict markers (fail on unknown markers)
+    --strict-markers
+
+# Markers for test categorization
+markers =
+    unit: Unit tests for individual functions
+    integration: Integration tests for policy application
+    e2e: End-to-end workflow tests
+    slow: Tests that take significant time
+    requires_network: Tests that require network access
+
+# Logging
+log_cli = false
+log_cli_level = INFO
+log_cli_format = %(asctime)s [%(levelname)8s] %(message)s
+log_cli_date_format = %Y-%m-%d %H:%M:%S
+
+# Warnings
+filterwarnings =
+    error
+    ignore::DeprecationWarning
+    ignore::PendingDeprecationWarning