Implement support for generic OpenAI api (#213)

* Implement support for generic OpenAI api

- Implements support to route requests to any openAI capable provider ( Deepsek, Qwen, VLLM, LM Studio, Ollama ).
- Keeps support for pure OpenAI and uses the new better responses api
- Uses the /chat/completions api for the generic providers
- If uri_base is not set, uses default implementation.

* Fix json handling and indentation

* Fix linter error indent

* Fix tests to set env vars

* Fix updating settings

* Change to prefix checking for OAI models

* FIX check model if custom uri is set

* Change chat to sync calls

Some local models don't support streaming. Revert to sync calls for generic OAI api

* Fix tests

* Fix tests

* Fix for gpt5 message extraction

- Finds the message output by filtering for "type" == "message" instead of assuming it's at index 0
- Safely extracts the text using safe navigation operators (&.)
- Raises a clear error if no message content is found
- Parses the JSON as before

* Add more langfuse logging

- Add Langfuse to auto categorizer and merchant detector
- Fix monitoring on streaming chat responses
- Add Langfuse traces also for model errors now

* Update app/models/provider/openai.rb

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: soky srm <sokysrm@gmail.com>

* handle nil function results explicitly

* Exposing some config vars.

* Linter and nitpick comments

* Drop back to `gpt-4.1` as default for now

* Linter

* Fix for strict tool schema in Gemini

- This fixes tool calling in Gemini OpenAI api
- Fix for getTransactions function, page size is not used.

---------

Signed-off-by: soky srm <sokysrm@gmail.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: Juan José Mata <juanjo.mata@gmail.com>

app/models/assistant/function/get_transactions.rb

@@ -68,7 +68,7 @@ class Assistant::Function::GetTransactions < Assistant::Function
 
   def params_schema
     build_schema(
-      required: [ "order", "page", "page_size" ],
+      required: [ "order", "page" ],
       properties: {
         page: {
           type: "integer",

app/models/assistant/responder.rb

@@ -11,6 +11,9 @@ class Assistant::Responder
   end
 
   def respond(previous_response_id: nil)
+    # Track whether response was handled by streamer
+    response_handled = false
+
     # For the first response
     streamer = proc do |chunk|
       case chunk.type
@@ -18,6 +21,7 @@ class Assistant::Responder
         emit(:output_text, chunk.data)
       when "response"
         response = chunk.data
+        response_handled = true
 
         if response.function_requests.any?
           handle_follow_up_response(response)
@@ -27,7 +31,16 @@ class Assistant::Responder
       end
     end
 
-    get_llm_response(streamer: streamer, previous_response_id: previous_response_id)
+    response = get_llm_response(streamer: streamer, previous_response_id: previous_response_id)
+
+    # For synchronous (non-streaming) responses, handle function requests if not already handled by streamer
+    unless response_handled
+      if response && response.function_requests.any?
+        handle_follow_up_response(response)
+      elsif response
+        emit(:response, { id: response.id })
+      end
+    end
   end
 
   private