Implement skill self-evolution and skill_manage flow (#1874)

* chore: ignore .worktrees directory

* Add skill_manage self-evolution flow

* Fix CI regressions for skill_manage

* Address PR review feedback for skill evolution

* fix(skill-evolution): preserve history on delete

* fix(skill-evolution): tighten scanner fallbacks

* docs: add skill_manage e2e evidence screenshot

* fix(skill-manage): avoid blocking fs ops in session runtime

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/packages/harness/deerflow/tools/__init__.py

@@ -1,3 +1,11 @@
 from .tools import get_available_tools
 
-__all__ = ["get_available_tools"]
+__all__ = ["get_available_tools", "skill_manage_tool"]
+
+
+def __getattr__(name: str):
+    if name == "skill_manage_tool":
+        from .skill_manage_tool import skill_manage_tool
+
+        return skill_manage_tool
+    raise AttributeError(name)