fix(providers): normalize vertex location case before validating

Hostnames are case-insensitive, so a mixed-case location like US-Central1
reaches Google today. Lowercase it before the region check rather than
rejecting an input that currently works.

Author: waleedlatif1

apps/sim/providers/vertex/index.test.ts

@@ -91,6 +91,12 @@ describe('vertexProvider location and project validation', () => {
     expect(mockExecuteGeminiRequest).toHaveBeenCalledTimes(1)
   })
 
+  it('normalizes a mixed-case location rather than rejecting it', async () => {
+    await vertexProvider.executeRequest(request({ vertexLocation: 'US-Central1' }))
+
+    expect(genAIArgs[0]).toMatchObject({ location: 'us-central1' })
+  })
+
   it('defaults to us-central1 when no location is supplied', async () => {
     await vertexProvider.executeRequest(request())
 

apps/sim/providers/vertex/index.ts

@@ -35,7 +35,13 @@ export const vertexProvider: ProviderConfig = {
     request: ProviderRequest
   ): Promise<ProviderResponse | StreamingExecution> => {
     const vertexProject = request.vertexProject || env.VERTEX_PROJECT
-    const vertexLocation = request.vertexLocation || env.VERTEX_LOCATION || 'us-central1'
+    // Hostnames are case-insensitive, so a mixed-case location reaches Google fine
+    // today. Normalize before validating rather than rejecting it as malformed.
+    const vertexLocation = (
+      request.vertexLocation ||
+      env.VERTEX_LOCATION ||
+      'us-central1'
+    ).toLowerCase()
 
     if (!vertexProject) {
       throw new Error(