Add duplicate scan session handling in SocketClient

- Implemented a check in the `startScanSession` method to prevent starting a new scan session if one is already in progress for the same session ID.
- Added logging to inform when a duplicate scan session is ignored, enhancing visibility into scan session management.
- Updated callback behavior to indicate when a scan session is already running, improving user feedback during scan operations.

src/socket/socketclient.js

@@ -765,6 +765,18 @@ export class SocketClient {
     const startToken = {};
     this.scanSessionTokens.set(sessionId, startToken);
 
+    const existing = this.scanSessions.get(sessionId);
+    if (existing?.scanning) {
+      logger.info(
+        "Scan session already running, ignoring duplicate start:",
+        sessionId,
+      );
+      if (typeof callback === "function") {
+        callback({ success: true, sessionId, alreadyRunning: true });
+      }
+      return;
+    }
+
     await this.stopScanSession(sessionId);
 
     if (this.scanSessionTokens.get(sessionId) !== startToken) {