better error handling

Author: simon-massa

lua/CopilotChat/client.lua

@@ -252,7 +252,13 @@ function Client:models()
 
         local ok, headers = pcall(self.authenticate, self, provider_name)
         if not ok then
-          log.warn('Failed to authenticate with ' .. provider_name .. ': ' .. headers)
+          log.error('Failed to authenticate with ' .. provider_name .. ': ' .. headers)
+          local user_err_msg = 'Failed to authenticate with ' .. provider_name
+          -- append error details, if available
+          if headers.error_details and headers.error_details.message then
+            user_err_msg = user_err_msg .. ' the server replied : ' .. headers.error_details.message
+          end
+          error(user_err_msg)
           return {}
         end