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/provider/openai/generic_chat_parser.rb

@@ -0,0 +1,60 @@
+class Provider::Openai::GenericChatParser
+  Error = Class.new(StandardError)
+
+  def initialize(object)
+    @object = object
+  end
+
+  def parsed
+    ChatResponse.new(
+      id: response_id,
+      model: response_model,
+      messages: messages,
+      function_requests: function_requests
+    )
+  end
+
+  private
+    attr_reader :object
+
+    ChatResponse = Provider::LlmConcept::ChatResponse
+    ChatMessage = Provider::LlmConcept::ChatMessage
+    ChatFunctionRequest = Provider::LlmConcept::ChatFunctionRequest
+
+    def response_id
+      object.dig("id")
+    end
+
+    def response_model
+      object.dig("model")
+    end
+
+    def message_choice
+      object.dig("choices", 0, "message")
+    end
+
+    def messages
+      content = message_choice&.dig("content")
+      return [] if content.blank?
+
+      [
+        ChatMessage.new(
+          id: response_id,
+          output_text: content
+        )
+      ]
+    end
+
+    def function_requests
+      tool_calls = message_choice&.dig("tool_calls") || []
+
+      tool_calls.map do |tool_call|
+        ChatFunctionRequest.new(
+          id: tool_call.dig("id"),
+          call_id: tool_call.dig("id"),
+          function_name: tool_call.dig("function", "name"),
+          function_args: tool_call.dig("function", "arguments")
+        )
+      end
+    end
+end