feat: add user token secret management for channels

- Implemented user token secret generation and retrieval in channel service.
- Added ResetUserTokenSecret method to reset the user token secret for channels.
- Updated channel configuration parsing to include user token secret.
- Enhanced WebSocket service to utilize user token secret for external info retrieval.
- Modified dashboard channel edit component to support user token secret display and reset functionality.
- Introduced API endpoint for resetting user token secret.
- Updated IM and SDK configurations to include user token.
- Added tests for user token verification logic.

web/lib/sdk/cs-ai-agent-sdk.js

@@ -48,6 +48,9 @@
     }
     merged.channelId = String(merged.channelId || "");
     merged.externalSource = String(merged.externalSource || "web_chat");
+    if (merged.userToken) {
+      merged.userToken = String(merged.userToken);
+    }
     return merged;
   }
 
@@ -67,6 +70,7 @@
     if (config.apiBaseUrl) frameUrl.searchParams.set("apiBaseUrl", config.apiBaseUrl);
     if (config.externalSource) frameUrl.searchParams.set("externalSource", config.externalSource);
     if (config.externalName) frameUrl.searchParams.set("externalName", config.externalName);
+    if (config.userToken) frameUrl.searchParams.set("userToken", config.userToken);
     return frameUrl;
   }