Docs: add Qwen Portal provider

docs/plugin.md

@@ -43,6 +43,7 @@ See [Voice Call](/plugins/voice-call) for a concrete example plugin.
 - [Microsoft Teams](/channels/msteams) — `@clawdbot/msteams`
 - Google Antigravity OAuth (provider auth) — bundled as `google-antigravity-auth` (disabled by default)
 - Gemini CLI OAuth (provider auth) — bundled as `google-gemini-cli-auth` (disabled by default)
+- Qwen Portal OAuth (provider auth) — bundled as `qwen-portal-auth` (disabled by default)
 - Copilot Proxy (provider auth) — bundled as `copilot-proxy` (disabled by default)
 
 Clawdbot plugins are **TypeScript modules** loaded at runtime via jiti. They can