Fix skill duplication in list output

Skills were appearing multiple times because the same skill directory
was being stored with different keys based on the full source path.
Changed SkillParser to use the skill directory name instead of the
full relative path for generating skill keys, preventing duplicates.

Before: keys like 'owner/repo:plugins/subdir/skill' and 'owner/repo:skill'
After: keys like 'owner/repo:skill' (using directory name only)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: James Zhu

code_assistant_manager/fetching/parsers.py

@@ -82,7 +82,7 @@ def parse_from_file(
 
         # Create skill entity
         skill = Skill(
-            key=self.create_entity_key(repo_config, source_directory),
+            key=self.create_entity_key(repo_config, directory),
             name=meta.get("name", directory),
             description=meta.get("description", ""),
             directory=directory,