add openai responses parameter test cases

[knjiang]

Add parameter test cases for openai responses with the new params.ts file

new test coverage, got the request body from https://platform.openai.com/docs/api-reference/responses:

Category	Before (existing)	After (new params.ts)
Reasoning	effort (3 values), summary	✓ (already covered)
Text config	verbosity	+ json_object, json_schema
Tools	function type, auto choice	+ web_search, code_interpreter, specific choice, parallel_tool_calls
Context	-	+ instructions, truncation
Storage	-	+ store
Caching	-	+ service_tier, prompt_cache_key
Metadata	-	+ metadata, safety_identifier

cross compatability coverage report -> https://github.com/braintrustdata/lingua/actions/runs/21009330639

[knjiang]

• add universal param configs #61
• add anthropic messages parameter test cases #59
• add chat completion parameter test cases #58
• add openai responses parameter test cases #54 👈 (View in Graphite)
• main

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