Add slash command support to OpenClaw WeChat channel

[thisnick]

Problem

The WeChat OpenClaw channel does not handle slash commands (e.g. /reset, /status). We set CommandBody: rawBody but are missing:

• hasControlCommand() — detect if a message is a control command
• resolveControlCommandGate() — authorization check for who can run commands
• CommandAuthorized flag in the inbound context payload
• BodyForCommands field

Without CommandAuthorized: true, OpenClaw ignores slash commands from incoming messages.

Reference

BlueBubbles extension (monitor.ts) has a full implementation of command gating with access group support. WhatsApp likely similar.

Tasks

• Add hasControlCommand check before dispatch
• Add resolveControlCommandGate for group authorization
• Set CommandAuthorized and BodyForCommands in context payload
• Allow commands to bypass mention gating in groups (when authorized)

[thisnick]

Fixed with this: #65