fix: use correct event subscription format for opencode

.opencode/plugin/superpowers.js

@@ -79,7 +79,8 @@ ${content}`;
       }
     ],
 
-    'session.created': async () => {
+    event: async ({ event }) => {
+      if (event.type === 'session.created') {
         const usingSuperpowersPath = skillsCore.resolveSkillPath('using-superpowers', superpowersSkillsDir, personalSkillsDir);
 
         let usingSuperpowersContent = '';
@@ -125,5 +126,6 @@ ${toolMapping}${updateNotice}
 </EXTREMELY_IMPORTANT>`
         };
       }
+    }
   };
 };