v2.1.0 — User-audit round: precise rate limiting, delete confirm gate, clean npm audit

All findings from a post-2.0.0 security/behavior audit.

Changed

• Rate limiter counts only FAILED unlocks — reject at cap first, record on wrong password, clear on success; a legit user can no longer lock a doc for others by unlocking it repeatedly
• delete_shared_doc requires confirm: true — explicit-consent gate for an irreversible agent-exposed tool
• Gist content search filters before the limit (matches beyond the newest 20 are found)
• Gist append updates the local search excerpt only after the GitHub PATCH succeeds

Fixed

• npm audit clean: transitive @hono/node-server pinned ≥2.0.5 via overrides (unused by this package's stdio/native-http paths; all 70 tests pass)
• README: gist index privacy wording (stores first 200 chars for search, never full content), install examples pinned to @^2 so future breaking releases can't change behavior on cold start, Windows daemon options

70 offline tests. CHANGELOG