39831fb61c
WeCom AI Bot does not strip @mention from text.content in group chats, causing all slash commands (/stop, /clear, /help) to fail — the content arrives as "@BotName /stop" instead of "/stop". - Add stripAtMentionBasic (stateless) and stripAtMention (with bot name caching) to handle multi-word bot display names - Support bot_name in channel credentials for immediate precision - Apply stripping in both WebSocket and webhook adapters, text and mixed - Add mention_test.go with 21 test cases