chore: use only gpt-5 model

.github/workflows/issue-validation.yml

@@ -92,7 +92,7 @@ jobs:
             - Each array item must be under 80 characters
             - overall_assessment must be under 100 characters
             - Output ONLY the JSON object, nothing else
-          model: openai/gpt-5
+          model: gpt-5
 
       - name: Check if first-time contributor
         id: check-first-time

.github/workflows/release-notes-generator.yml

@@ -122,7 +122,7 @@ jobs:
             - If commits are unclear, infer the purpose from the context
 
             The application is a desktop app built with Tauri + Next.js that helps users manage multiple browser profiles with proxy support.
-          model: gpt-4o
+          model: gpt-5
 
       - name: Update release with generated notes
         if: steps.get-release.outputs.is-prerelease == 'false'