chore(catalog): bump config-audit ref v5.4.1 -> v5.5.0

Plugin v5.5.0 (steering-model I: A+E) is tagged and pushed; this points
the marketplace source.ref at it so installs track the real release.
Scanner count unchanged (13), so the README prose stays accurate.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ter3E2JSi1Khgmuf2kady8

.claude-plugin/marketplace.json

@@ -24,7 +24,7 @@
       "source": {
         "source": "url",
         "url": "https://git.fromaitochitta.com/open/config-audit.git",
-        "ref": "v5.4.1"
+        "ref": "v5.5.0"
       },
       "description": "Multi-agent workflow for analyzing, reporting, and optimizing Claude Code configuration across your entire machine"
     },