feat: improve Settings page retry config UI and enhance excludedModels API support

- Reorganize retry settings into separate Card for better visual hierarchy
  - Move retry update button inline with input field via rightElement
  - Add excluded-models serialization in provider key configuration
  - Add excluded-models normalization support in API transformers with fallback parsing

src/services/api/providers.ts

@@ -54,6 +54,9 @@ const serializeProviderKey = (config: ProviderKeyConfig) => {
   if (headers) payload.headers = headers;
   const models = serializeModelAliases(config.models);
   if (models && models.length) payload.models = models;
+  if (config.excludedModels && config.excludedModels.length) {
+    payload['excluded-models'] = config.excludedModels;
+  }
   return payload;
 };