Feishu Cli Doc Guide

This is a reference spec for generating Feishu-compatible Markdown, not something you call directly. It documents the hard-learned lessons from importing 10,000+ lines of documentation into Feishu: how Mermaid flowchart labels with curly braces break rendering, why sequence diagrams fail above 8 participants, the fact that `\n` in node labels just displays literally instead of breaking lines (use `<br>` instead), and how tables wider than 9 columns need to be split while preserving the first column as an identifier. It covers 8 Mermaid diagram types, PlantUML gotchas like forbidden visibility markers in class diagrams, and the 6 supported Callout types. Written in Chinese but the rules are universal. If you're building anything that writes to Feishu programmatically, this is the cheat sheet that keeps your imports from silently failing.