feat(providers): add extra_query config for OpenAI-compatible providers

[axelray-dev]

Addresses the extra_query portion of #4204.

Summary

Some Azure-style gateways require ?api-version= query params on the chat-completions endpoint. This adds a ProviderConfig.extra_query field, threaded through the factory into AsyncOpenAI(default_query=...), so users can configure query params via JSON config.

The provider_signature tuple now includes extra_query so per-turn refresh rebuilds the provider when the value changes.

This PR implements only the extra_query part of #4204. The max_completion_tokens model-awareness enhancement is intentionally left as a separate change.

Changes

• nanobot/config/schema.py: Add extra_query: dict[str, str] | None = None to ProviderConfig
• nanobot/providers/factory.py: Thread extra_query into OpenAICompatProvider constructor and provider_signature
• nanobot/providers/openai_compat_provider.py: Accept extra_query param, store it, pass default_query= to AsyncOpenAI
• tests/providers/test_extra_query_config.py: 8 new tests (schema, init, build_client, signature)
• tests/agent/test_runner_fallback.py: Update signature tuple index (shifted by +1 from extra_query insertion)

Testing

Verified locally

• pytest tests/providers/test_extra_query_config.py -v: 8/8 passed
• pytest tests/providers/test_extra_body_config.py tests/agent/test_runner_fallback.py -v: 48/48 passed (no regressions)
• ruff check on all changed files: all checks passed
• git diff --check: clean

Added or updated tests

8 new tests in tests/providers/test_extra_query_config.py:

• Schema acceptance (default None, accepts dict)
• Provider storage (default empty, None becomes empty, dict stored)
• Client construction (default_query passed to AsyncOpenAI, None when empty)
• Signature tracking (extra_query changes produce different signatures)

QA follow-up

• Test with a real Azure-style gateway to confirm ?api-version= is appended to requests
• Confirm that extra_query in the config JSON maps correctly via camelCase alias

Checklist

• I have read the CONTRIBUTING guide
• Tests pass locally
• Linting passes locally (ruff)