Fix #17: Convert requirements-clarity to correct plugin directory format

- Remove commands/ and agents/ directories
- Create skills/ directory with SKILL.md
- Update marketplace.json to reference skills instead of commands/agents
- Maintain all functionality in proper Claude Skills format

Generated by swe-agent

requirements-clarity/.claude-plugin/marketplace.json

@@ -20,10 +20,7 @@
   ],
   "category": "essentials",
   "strict": false,
-  "commands": [
-    "./commands/clarif.md"
-  ],
-  "agents": [
-    "./agents/clarif-agent.md"
+  "skills": [
+    "./skills/SKILL.md"
   ]
 }