fix: allow user headers to override default headers and clean up formatting

- Reorder header spread in router-provider.ts so user-provided openAiHeaders can override DEFAULT_HEADERS
- Remove unnecessary blank lines after imports for consistency
- This matches the pattern used in openai.ts where DEFAULT_HEADERS come first

Author: daniel-lxs

src/api/providers/fetchers/litellm.ts

@@ -5,8 +5,6 @@ import { LITELLM_COMPUTER_USE_MODELS } from "@roo-code/types"
 import type { ModelRecord } from "../../../shared/api"
 
 import { DEFAULT_HEADERS } from "../constants"
-
-
 /**
  * Fetches available models from a LiteLLM server
  *
@@ -19,7 +17,7 @@ export async function getLiteLLMModels(apiKey: string, baseUrl: string): Promise
 	try {
 		const headers: Record<string, string> = {
 			"Content-Type": "application/json",
-			...DEFAULT_HEADERS
+			...DEFAULT_HEADERS,
 		}
 
 		if (apiKey) {

src/api/providers/router-provider.ts

@@ -9,7 +9,6 @@ import { getModels } from "./fetchers/modelCache"
 
 import { DEFAULT_HEADERS } from "./constants"
 
-
 type RouterProviderOptions = {
 	name: RouterName
 	baseURL: string
@@ -50,9 +49,9 @@ export abstract class RouterProvider extends BaseProvider {
 			baseURL,
 			apiKey,
 			defaultHeaders: {
+				...DEFAULT_HEADERS,
 				...(options.openAiHeaders || {}),
-				...DEFAULT_HEADERS
-			}
+			},
 		})
 	}