fix: critical plugin structure and configuration fixes

- Fix hooks.json: use valid PostToolUse event (not invalid task-completed)
- Move projman/plugin.json to projman/.claude-plugin/plugin.json
- Fix projman/.mcp.json to use venv python paths
- Add cmdb-assistant to marketplace.json
- Update .gitignore: allow .env files (private repo)
- Fix create_labels.py: use env vars instead of hardcoded token
- Add CLAUDE.md critical rules section to prevent future mistakes

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

project-hygiene/hooks/hooks.json

@@ -1,9 +1,15 @@
 {
-  "hooks": [
-    {
-      "event": "task-completed",
-      "script": "${CLAUDE_PLUGIN_ROOT}/hooks/cleanup.sh",
-      "description": "Post-task cleanup: remove temp files, warn about unexpected root files, manage orphans"
-    }
-  ]
+  "hooks": {
+    "PostToolUse": [
+      {
+        "matcher": "Write|Edit",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/cleanup.sh"
+          }
+        ]
+      }
+    ]
+  }
 }