fix(provider/azure): lint err

pkg/providers/azure/provider.go

@@ -128,7 +128,7 @@ func (p *Provider) Chat(
 	// Azure uses api-key header instead of Authorization: Bearer
 	req.Header.Set("Content-Type", "application/json")
 	if p.apiKey != "" {
-		req.Header.Set("api-key", p.apiKey)
+		req.Header.Set("Api-Key", p.apiKey)
 	}
 
 	resp, err := p.httpClient.Do(req)

pkg/providers/azure/provider_test.go

@@ -53,7 +53,7 @@ func TestProviderChat_AzureAuthHeader(t *testing.T) {
 	var capturedAuth string
 
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		capturedAPIKey = r.Header.Get("api-key")
+		capturedAPIKey = r.Header.Get("Api-Key")
 		capturedAuth = r.Header.Get("Authorization")
 		writeValidResponse(w)
 	}))