● 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.

MANIFEST.in

@@ -11,4 +11,5 @@ include extras.json
 include github-stats.json
 include model-list.json
 include alter-list.json
-include comfyui_manager/channels.list.template
+include comfyui_manager/channels.list.template
+include comfyui_manager/pip-policy.json