SIA v1.7.0 — clean MCP tool names

SIA now advertises bare MCP tool names, so clients show the clean public surface sia.ask, sia.search, sia.recall, sia.status, sia.think, sia.note, sia.propose_take, and sia.calibration instead of sia.sia_*.

Legacy raw sia_* names remain accepted as hidden inbound aliases for existing sessions, but they are never advertised. Restart or reconnect MCP clients after updating so cached discovery refreshes. The README, Field Manual, agent skill, and release metadata all carry the migration.

Verified by the observed 859-test suite, a successful live v1.7.0 install, sia ready, and a direct resident tools/list response containing only the clean names.