test(webviewMessageHandler): correct LiteLLM credential priority assertion

The test "prefers config values over message values for LiteLLM" was
asserting the old || behavior. The handler now uses ?? so message.values
takes precedence over saved config, matching the DeepSeek pattern and
allowing unsaved settings UI state to be used during Sync Models.

Author: awschmeder

src/core/webview/__tests__/webviewMessageHandler.spec.ts

@@ -629,7 +629,7 @@ describe("webviewMessageHandler - requestRouterModels", () => {
 		})
 	})
 
-	it("prefers config values over message values for LiteLLM", async () => {
+	it("prefers message values over config values for LiteLLM", async () => {
 		const mockModels: ModelRecord = {}
 		mockGetModels.mockResolvedValue(mockModels)
 
@@ -641,11 +641,11 @@ describe("webviewMessageHandler - requestRouterModels", () => {
 			},
 		})
 
-		// Verify config values are used over message values
+		// Verify message values take precedence over saved config (current unsaved field state wins)
 		expect(mockGetModels).toHaveBeenCalledWith({
 			provider: "litellm",
-			apiKey: "litellm-key", // From config
-			baseUrl: "http://localhost:4000", // From config
+			apiKey: "message-key", // From message.values
+			baseUrl: "http://message-url", // From message.values
 		})
 	})
 })