fix(plugins): align HOL plugin icons (#123)

Signed-off-by: Michael Kantor <6068672+kantorcodes@users.noreply.github.com>

Author: kantorcodes

.agents/plugins/marketplace.json

@@ -382,7 +382,7 @@
       },
       "category": "Development & Workflow",
       "description": "Delegate tasks to specialist AI agents via the HOL Registry, plan, find, summon, and recover sessions.",
-      "icon": "./plugins/hashgraph-online/registry-broker-codex-plugin/assets/icon.svg"
+      "icon": "./plugins/hashgraph-online/registry-broker-codex-plugin/assets/icon.png"
     },
     {
       "name": "session-orchestrator",

plugins/hashgraph-online/registry-broker-codex-plugin/.codex-plugin/plugin.json

@@ -42,7 +42,7 @@
       "Delegate this bounded task through Registry Broker and keep the session trail."
     ],
     "brandColor": "#0F766E",
-    "composerIcon": "./assets/icon.svg",
+    "composerIcon": "./assets/icon.png",
     "logo": "./assets/logo.svg",
     "screenshots": [
       "./assets/screenshot-summon.png",