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>

test/controllers/settings/hostings_controller_test.rb

@@ -20,6 +20,8 @@ class Settings::HostingsControllerTest < ActionDispatch::IntegrationTest
   end
 
   test "cannot edit when self hosting is disabled" do
+    @provider.stubs(:usage).returns(@usage_response)
+
     with_env_overrides SELF_HOSTED: "false" do
       get settings_hosting_url
       assert_response :forbidden
@@ -54,6 +56,48 @@ class Settings::HostingsControllerTest < ActionDispatch::IntegrationTest
     end
   end
 
+  test "can update openai uri base and model together when self hosting is enabled" do
+    with_self_hosting do
+      patch settings_hosting_url, params: { setting: { openai_uri_base: "https://api.example.com/v1", openai_model: "gpt-4" } }
+
+      assert_equal "https://api.example.com/v1", Setting.openai_uri_base
+      assert_equal "gpt-4", Setting.openai_model
+    end
+  end
+
+  test "cannot update openai uri base without model when self hosting is enabled" do
+    with_self_hosting do
+      Setting.openai_model = ""
+
+      patch settings_hosting_url, params: { setting: { openai_uri_base: "https://api.example.com/v1" } }
+
+      assert_response :unprocessable_entity
+      assert_match(/OpenAI model is required/, flash[:alert])
+      assert_nil Setting.openai_uri_base
+    end
+  end
+
+  test "can update openai model alone when self hosting is enabled" do
+    with_self_hosting do
+      patch settings_hosting_url, params: { setting: { openai_model: "gpt-4" } }
+
+      assert_equal "gpt-4", Setting.openai_model
+    end
+  end
+
+  test "cannot clear openai model when custom uri base is set" do
+    with_self_hosting do
+      Setting.openai_uri_base = "https://api.example.com/v1"
+      Setting.openai_model = "gpt-4"
+
+      patch settings_hosting_url, params: { setting: { openai_model: "" } }
+
+      assert_response :unprocessable_entity
+      assert_match(/OpenAI model is required/, flash[:alert])
+      assert_equal "gpt-4", Setting.openai_model
+    end
+  end
+
   test "can clear data cache when self hosting is enabled" do
     account = accounts(:investment)
     holding = account.holdings.first