Docs: refresh stale v1.5.1-era counts to v1.6.0 reality

llms.txt now states v1.6.0 with 946 tests and ~4,400 adversarial calls;
catalog number and the token-bill paragraph read 189 tools in all seven
languages.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: nometalalchemist