Preserve BFCL argument values in model schemas

[SonAIengine]

Summary

• Add deterministic model-facing schema hints for argument value preservation.
• Preserve boolean defaults, percentage-as-decimal rate values, open dict nesting, and query-local symbolic data references.
• Bump the BFCL model-case cache version because prompts/tool schemas changed.
• Document the Qwen 27B argument subset lift in the research notes.

Validation

• poetry run ruff check .
• poetry run ruff format --check .
• poetry run pytest tests/test_bfcl_tool_selection_llm_loop.py tests/test_bfcl_tool_selection_sweep.py -q -> 26 passed
• poetry run pytest tests/ -q -> 962 passed, 3 skipped, 1 warning
• Fresh Qwen 27B run on the 6-case argument mismatch subset: evaluator exact 1.0, retrieval@5 1.0, failure tags {}

Qwen smoke artifact

• /tmp/gtc-bfcl-argument-value-hints-v4-subset.json

Notes

• This is stacked on Prefer case-local BFCL tool schemas #52 because Tag BFCL argument mismatch causes #51/Prefer case-local BFCL tool schemas #52 are still open on GitHub.

[SonAIengine]

Closing this internal stacked PR as superseded by the current main branch. The branch is preserved for history.