removing model_server python module to brightstaff (function calling) (#615)

* adding function_calling functionality via rust

* fixed rendered YAML file

* removed model_server from envoy.template and forwarding traffic to bright_staff

* fixed bugs in function_calling.rs that were breaking tests. All good now

* updating e2e test to clean up disk usage

* removing Arch* models to be used as a default model if one is not specified

* if the user sets arch-function base_url we should honor it

* fixing demos as we needed to pin to a particular version of huggingface_hub else the chatbot ui wouldn't build

* adding a constant for Arch-Function model name

* fixing some edge cases with calls made to Arch-Function

* fixed JSON parsing issues in function_calling.rs

* fixed bug where the raw response from Arch-Function was re-encoded

* removed debug from supervisord.conf

* commenting out disk cleanup

* adding back disk space

---------

Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-288.local>
Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-342.local>

crates/hermesllm/src/providers/response.rs

@@ -316,6 +316,17 @@ impl TryFrom<(SseEvent, &SupportedAPIs, &SupportedUpstreamAPIs)> for SseEvent {
         // Create a new transformed event based on the original
         let mut transformed_event = sse_event;
 
+        // Handle [DONE] marker early - don't try to parse as JSON
+        if transformed_event.is_done() {
+            // For OpenAI client API, keep [DONE] as-is
+            // For Anthropic client API, it will be transformed via ProviderStreamResponseType
+            if matches!(client_api, SupportedAPIs::OpenAIChatCompletions(_)) {
+                // Keep the [DONE] marker as-is for OpenAI clients
+                transformed_event.sse_transform_buffer = "data: [DONE]".to_string();
+                return Ok(transformed_event);
+            }
+        }
+
         // If has data, parse the data as a provider stream response (business logic layer)
         if transformed_event.data.is_some() {
             let data_str = transformed_event.data.as_ref().unwrap();