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>

.env.local.example

@@ -1,13 +1,22 @@
 # To enable / disable self-hosting features.
-SELF_HOSTED=true
+SELF_HOSTED = true
 
 # Enable Twelve market data (careful, this will use your API credits)
-TWELVE_DATA_API_KEY=
+TWELVE_DATA_API_KEY =
+
+# OpenAI-compatible API endpoint config
+OPENAI_ACCESS_TOKEN =
+OPENAI_URI_BASE =
+OPENAI_MODEL =
+
+# (example: LM Studio/Docker config) OpenAI-compatible API endpoint config
+# OPENAI_URI_BASE = http://host.docker.internal:1234/
+# OPENAI_MODEL = qwen/qwen3-vl-4b
 
 # Langfuse config
-LANGFUSE_PUBLIC_KEY=
-LANGFUSE_SECRET_KEY=
-LANGFUSE_HOST=https://cloud.langfuse.com
+LANGFUSE_PUBLIC_KEY =
+LANGFUSE_SECRET_KEY =
+LANGFUSE_HOST = https://cloud.langfuse.com
 
 # Set to `true` to get error messages rendered in the /chats UI
-AI_DEBUG_MODE=
+AI_DEBUG_MODE =