fix: strip unsupported params for reasoning models & handle UnboundLocalError in Generator

[YardonYan]

Fixes #481

Summary

Two bugs fixed for Issue #481 (Quickstart Colab fails with frequency_penalty error on reasoning models):

Bug 1: Reasoning models reject unsupported Chat Completion params

OpenAI Responses API rejects \requency_penalty, \presence_penalty, \ emperature, and \ op_p\ for reasoning models (o1, o3-mini, etc.), causing \BadRequestError.

Fix: Added parameter filtering in \OpenAIClient.convert_inputs_to_api_kwargs()\ — when \model_type == ModelType.LLM_REASONING, these unsupported params are stripped from \inal_model_kwargs\ with a warning log.

Bug 2: \UnboundLocalError\ in \Generator._get_default_mapping()\

When both \output.data\ and \output.raw_response\ were \None\ (e.g. API call failure), the method raised \UnboundLocalError\ because \output_mapping\ and \output_fields\ were never assigned.

Fix: Added an \else\ branch returning empty \output_mapping={}\ and \output_fields=[]\ with a warning log.

Root Cause Analysis (Issue #481)

1. User runs Quickstart Colab with a reasoning model (e.g. o3-mini)
2. \compose_model_kwargs\ merges default model_kwargs including \requency_penalty\
3. \OpenAIClient\ passes \requency_penalty\ to OpenAI Responses API → \BadRequestError\
4. API call fails → \output.data\ and \output.raw_response\ are both None
5. _get_default_mapping()\ has no else branch → \UnboundLocalError\

Tests Added (6 new, all passing)

• \ est_convert_inputs_to_api_kwargs_reasoning_model_strips_unsupported_params\
• \ est_convert_inputs_to_api_kwargs_llm_keeps_all_params\
• \TestGetDefaultMapping\ class with 4 test cases:
  • \ est_data_with_output_fields\ — normal case
  • \ est_raw_response_only\ — fallback to raw_response
  • \ est_both_data_and_raw_response_none\ — the UnboundLocalError fix
  • \ est_data_none_raw_response_empty_string\ — edge case

Files Changed

• \�dalflow/adalflow/components/model_client/openai_client.py\ — strip unsupported params for LLM_REASONING
• \�dalflow/adalflow/core/generator.py\ — add else branch in _get_default_mapping
• \�dalflow/tests/test_openai_client.py\ — 2 new test methods
• \�dalflow/tests/test_generator.py\ — new TestGetDefaultMapping class (4 tests)