create-favicon

Language: Match the user’s language (中文提问则中文回复).

Normative references (read before generating)

1. references/ico-format-and-browser-notes.md — ICO 结构、MIME、尺寸与 Apple Touch Icon 说明。
2. USAGE.md — 输入输出约定与无图门禁话术。

Step 0 · Mandatory source image gate（必须最先执行）

DO NOT resize, pack ICO, or write favicon.ico until a usable source image is confirmed.

Treat the source as present only if 至少一项成立：