feat(deps): add unified dependency resolver using uv pip compile

- Add UnifiedDepResolver module with 7 FRs: collect, compile, install pipeline
- Integrate startup batch resolution in prestartup_script.py (module scope)
- Skip per-node pip install in execute_install_script() when unified mode active
- Add use_unified_resolver config flag following use_uv pattern
- Input sanitization: reject -r, -e, --find-links, @ file://, path separators
- Handle --index-url/--extra-index-url separation with credential redaction
- Fallback to per-node pip on resolver failure or uv unavailability
- Add 98 unit tests across 20 test classes
- Add PRD and Design docs with cm_global integration marked as DEFERRED

.gitignore

@@ -21,4 +21,6 @@ check2.sh
 build
 dist
 *.egg-info
-.env
+.env
+.claude
+test_venv