fix: address code review feedback for CometAPI provider

- Remove duplicate schema entry in provider-settings.ts
- Remove try-catch from fetchModel to match DeepInfraHandler pattern
- Add timeout support to RouterProvider base class
- Store apiKey and baseURL in RouterProvider for model fetching
- Add comprehensive test coverage for CometAPI provider
- Fix test mock structure for streaming responses

Author: roomote

packages/types/src/provider-settings.ts

@@ -427,7 +427,6 @@ export const providerSettingsSchema = z.object({
 	...qwenCodeSchema.shape,
 	...rooSchema.shape,
 	...vercelAiGatewaySchema.shape,
-	...cometApiSchema.shape,
 	...codebaseIndexProviderSchema.shape,
 })