fix: extract markdown from structured responses in bot menu handler

fix: remove bot menu API registration (must be configured in console)

feat: add bot menu for p2p chats (status, cancel, doctor)

fix: use message_type instead of msg_type for Feishu message parsing

feat: add inbound file and image receiving from Feishu

feat: add crash protection and auto-restart guardian

feat: support multi-target round-robin rotation for Gemini readonly classifier

fix: address audit findings H1-H4, M2/M6/M9/M10/M11, L5

docs: expand approval design summary in README, remove audit docs from repo

docs: add approval system design document (bilingual)

docs: add bilingual README, complete env reference, audit findings, MIT license

Initial Feishu bridge import