Run deterministic rewrite hints inside deep search

[SonAIengine]

Summary

• add deterministic query rewrite hints for noisy numeric years and "created/made/formed from" process questions
• run bounded rewrite searches inside deep_search and merge their evidence before returning to the LLM
• project hints before large tool data so agents see corrective actions early

Validation

• uv run ruff format --check src/synaptic/agent_loop.py src/synaptic/agent_tools.py src/synaptic/agent_tools_v2.py tests/test_agent_tools.py tests/test_agent_loop_projection.py
• uv run ruff check src/synaptic/agent_loop.py src/synaptic/agent_tools.py src/synaptic/agent_tools_v2.py tests/test_agent_tools.py tests/test_agent_loop_projection.py
• uv run pytest tests/test_agent_tools.py tests/test_agent_efficiency.py tests/test_agent_search_benchmarks.py tests/test_agent_loop_projection.py
• Deterministic full-corpus check: 91711 and 237373 gold docs rank 1 in deep_search after auto rewrites
• DeepSeek live smoke on those two prior misses: 0/2 -> 2/2, both first relevant at turn 1 / call 1