dsh-plugin-wechat-bridge: Bridge WeChat private chats into DSH agent sessions

dsh-plugin-wechat-bridge is an MIT-licensed DSH plugin that bridges WeChat private chat messages into DSH agent sessions, allowing users to drive the agent and receive replies via their phone even when away from their computer. Replies are sent back in plain text chunks (up to 4096 characters × 5 segments), with one independent session per person per day. The plugin supports crash-safe mechanisms such as hot-swappable start/stop, unidirectional session notifications (automatically buffering and resending upon token expiration), cross-process polling locks, and atomic state persistence; the inbound mechanism uses fail-safe.