feat(remote-connect): align WeChat ClawBot channel

[bobleer]

Summary

• simplify the WeChat Remote Connect setup by auto-starting after QR login, removing the redundant Connect action, and keeping the ClawBot delivery-window warning visible before and after connection
• align the iLink client with @tencent-weixin/openclaw-weixin 2.4.6, including QR verification/redirect/already-bound flows, request metadata, lifecycle notifications, context-token persistence, and server-driven long-polling
• add focused frontend and Rust contract coverage for the updated flow

Testing

• pnpm run type-check:web
• pnpm --dir src/web-ui run test:run src/app/components/RemoteConnectDialog/RemoteConnectDialog.contract.test.ts
• pnpm run i18n:audit
• cargo test -p bitfun-services-integrations --features remote-connect remote_connect::bot::weixin --lib
• cargo test -p bitfun-core service::remote_connect::bot::weixin::tests --lib
• cargo check --workspace