feat: add QQ Bot platform adapter (Official API v2)

Add full QQ Bot integration via the Official QQ Bot API (v2):
- WebSocket gateway for inbound events (C2C, group, guild, DM)
- REST API for outbound text/markdown/media messages
- Voice transcription (Tencent ASR + configurable STT provider)
- Attachment processing (images, voice, files)
- User authorization (allowlist + allow-all + DM pairing)

Integration points:
- gateway: Platform.QQ enum, adapter factory, allowlist maps
- CLI: setup wizard, gateway config, status display, tools config
- tools: send_message cross-platform routing, toolsets
- cron: delivery platform support
- docs: QQ Bot setup guide

hermes_cli/platforms.py

@@ -35,6 +35,7 @@ PLATFORMS: OrderedDict[str, PlatformInfo] = OrderedDict([
     ("wecom",          PlatformInfo(label="💬 WeCom",           default_toolset="hermes-wecom")),
     ("wecom_callback", PlatformInfo(label="💬 WeCom Callback",  default_toolset="hermes-wecom-callback")),
     ("weixin",         PlatformInfo(label="💬 Weixin",          default_toolset="hermes-weixin")),
+    ("qq",             PlatformInfo(label="💬 QQ",              default_toolset="hermes-qq")),
     ("webhook",        PlatformInfo(label="🔗 Webhook",         default_toolset="hermes-webhook")),
     ("api_server",     PlatformInfo(label="🌐 API Server",      default_toolset="hermes-api-server")),
 ])