Recover BFCL route planning retrieval

[SonAIengine]

Summary

• Add deterministic route-planning query expansion for fastest/best/optimal/shortest route intents.
• Boost route-planning tools when the user intent is split across operation text and parameter enum values, e.g. description says best route while method enum carries fastest.
• Add a regression test for the BFCL multiple_24 failure shape where chess/event context previously displaced the route planner.
• Update research docs to mark multiple_24 route retrieval miss as recovered and narrow the next bottleneck to sequence+3D over-decomposition.

Validation

• poetry run ruff check .
• poetry run ruff format --check .
• poetry run pytest tests/test_retrieval.py -q -> 14 passed
• poetry run pytest tests/ -q -> 968 passed, 3 skipped, 1 warning
• Deterministic BFCL retrieval all four categories: /tmp/gtc-bfcl-route-hardening-deterministic.json -> 1000 cases, recall@5 0.953, status pass
• BFCL multiple_24 deterministic: route_planner.calculate_route moved from rank 8 to rank 1; recall@1/3/5 1.00
• Fresh Qwen single-case smoke: /tmp/gtc-bfcl-route-hardening-multiple24-qwen.json -> evaluator exact 1.00, retrieved exact 1.00

Remaining Bottleneck

• parallel_3: model/tool selection over-decomposes by calling lower-level sequence-only plus sequence+3D tools together.

[SonAIengine]

Closing this internal stacked PR as superseded by the current main branch.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