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/src/lib/utils.ts

@@ -16,11 +16,6 @@ export function isCodexModel(model?: AgentModel | string): boolean {
     "gpt-5.1-codex",
     "gpt-5.1-codex-mini",
     "gpt-5.1",
-    "o3",
-    "o3-mini",
-    "o4-mini",
-    "gpt-4o",
-    "gpt-4o-mini",
   ];
   return codexModels.includes(model);
 }
@@ -45,11 +40,6 @@ export function getModelDisplayName(model: AgentModel | string): string {
     "gpt-5.1-codex": "GPT-5.1 Codex",
     "gpt-5.1-codex-mini": "GPT-5.1 Codex Mini",
     "gpt-5.1": "GPT-5.1",
-    o3: "OpenAI O3",
-    "o3-mini": "OpenAI O3 Mini",
-    "o4-mini": "OpenAI O4 Mini",
-    "gpt-4o": "GPT-4o",
-    "gpt-4o-mini": "GPT-4o Mini",
   };
   return displayNames[model] || model;
 }