feat: add feature-dev skill with 7-phase workflow

Structured feature development with codeagent orchestration:
- Discovery, Exploration, Clarification, Architecture phases
- Implementation, Review, Summary phases
- Parallel agent execution via code-explorer, code-architect, etc.
- Hook-based workflow automation with validation scripts

Generated with SWE-Agent.ai

Co-Authored-By: SWE-Agent.ai <noreply@swe-agent.ai>

skills/feature-dev/hooks/hooks.json

@@ -0,0 +1,15 @@
+{
+  "description": "Feature-dev loop hook for 7-phase workflow",
+  "hooks": {
+    "Stop": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/stop-hook.sh"
+          }
+        ]
+      }
+    ]
+  }
+}