chore: add renovate regex manager for opencode-ai

renovate.json

@@ -9,6 +9,15 @@
       "depNameTemplate": "n2-soul",
       "datasourceTemplate": "npm",
       "versioningTemplate": "npm"
+    },
+    {
+      "customType": "regex",
+      "description": "Track opencode-ai npm package pinned in Dockerfile RUN command",
+      "managerFilePatterns": ["/^Dockerfile$/"],
+      "matchStrings": ["opencode-ai@(?<currentValue>[^\\s]+)"],
+      "depNameTemplate": "opencode-ai",
+      "datasourceTemplate": "npm",
+      "versioningTemplate": "npm"
     }
   ]
 }