● 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/common/pip_util/test_unit_parsing.py

@@ -0,0 +1,178 @@
+"""
+Unit tests for package spec parsing and condition evaluation
+
+Tests core utility functions
+"""
+
+import subprocess
+from pathlib import Path
+
+import pytest
+
+
+@pytest.mark.unit
+def test_parse_package_spec_name_only(mock_manager_util, mock_context):
+    """Test parsing package name without version"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    name, spec = batch._parse_package_spec("numpy")
+
+    assert name == "numpy"
+    assert spec is None
+
+
+@pytest.mark.unit
+def test_parse_package_spec_exact_version(mock_manager_util, mock_context):
+    """Test parsing package with exact version"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    name, spec = batch._parse_package_spec("numpy==1.26.0")
+
+    assert name == "numpy"
+    assert spec == "==1.26.0"
+
+
+@pytest.mark.unit
+def test_parse_package_spec_min_version(mock_manager_util, mock_context):
+    """Test parsing package with minimum version"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    name, spec = batch._parse_package_spec("pandas>=2.0.0")
+
+    assert name == "pandas"
+    assert spec == ">=2.0.0"
+
+
+@pytest.mark.unit
+def test_parse_package_spec_hyphenated_name(mock_manager_util, mock_context):
+    """Test parsing package with hyphens"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    name, spec = batch._parse_package_spec("scikit-learn>=1.0")
+
+    assert name == "scikit-learn"
+    assert spec == ">=1.0"
+
+
+@pytest.mark.unit
+def test_evaluate_condition_none(mock_manager_util, mock_context):
+    """Test None condition always returns True"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    result = batch._evaluate_condition(None, "numpy", {})
+
+    assert result is True
+
+
+@pytest.mark.unit
+def test_evaluate_condition_installed_package_exists(mock_manager_util, mock_context):
+    """Test installed condition when package exists"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    condition = {"type": "installed", "package": "numpy"}
+    installed = {"numpy": "1.26.0"}
+
+    result = batch._evaluate_condition(condition, "numba", installed)
+
+    assert result is True
+
+
+@pytest.mark.unit
+def test_evaluate_condition_installed_package_not_exists(mock_manager_util, mock_context):
+    """Test installed condition when package doesn't exist"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    condition = {"type": "installed", "package": "numpy"}
+    installed = {}
+
+    result = batch._evaluate_condition(condition, "numba", installed)
+
+    assert result is False
+
+
+@pytest.mark.unit
+def test_evaluate_condition_platform_os_match(
+    mock_manager_util,
+    mock_context,
+    mock_platform_linux
+):
+    """Test platform OS condition matching"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    condition = {"type": "platform", "os": "linux"}
+
+    result = batch._evaluate_condition(condition, "package", {})
+
+    assert result is True
+
+
+@pytest.mark.unit
+def test_evaluate_condition_platform_gpu_available(
+    mock_manager_util,
+    mock_context,
+    mock_torch_cuda_available
+):
+    """Test GPU detection when available"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    condition = {"type": "platform", "has_gpu": True}
+
+    result = batch._evaluate_condition(condition, "package", {})
+
+    assert result is True
+
+
+@pytest.mark.unit
+def test_evaluate_condition_platform_gpu_not_available(
+    mock_manager_util,
+    mock_context,
+    mock_torch_cuda_unavailable
+):
+    """Test GPU detection when not available"""
+    import sys
+    # Path setup handled by conftest.py
+
+    from comfyui_manager.common.pip_util import PipBatch
+
+    batch = PipBatch()
+    condition = {"type": "platform", "has_gpu": True}
+
+    result = batch._evaluate_condition(condition, "package", {})
+
+    assert result is False