feat(ui): improve modal UX and model management

- Increase dialog max-width to 2xl for better content display
- Add tabbed interface to feature modal (prompt/model/testing)
- Streamline model selection with compact button layout
- Remove unused OpenAI O3/O4 models from registry
- Add model string validation and fallback logic
- Add "Uncategorized" category support

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>

app/electron/services/codex-cli-detector.js

@@ -212,10 +212,7 @@ class CodexCliDetector {
       'gpt-5.1-codex-max',
       'gpt-5.1-codex',
       'gpt-5.1-codex-mini',
-      'gpt-5.1',
-      'o3',
-      'o3-mini',
-      'o4-mini'
+      'gpt-5.1'
     ];
     return supportedModels.includes(model);
   }