refactor: scan Jupyter port range (8888-8895) during cleanup

- Change from single port 8888 to range 8888-8895
- Jupyter increments port when 8888 is busy, so we need to check multiple ports
- Add timing measurement for port-based cleanup phase
- Log cleanup duration for performance monitoring

The loop adds minimal overhead as each port check is fast when no process
is listening. Timing is logged at debug level for monitoring.

Author: jankuca

src/kernels/deepnote/deepnoteServerStarter.node.ts

@@ -839,12 +839,21 @@ export class DeepnoteServerStarter implements IDeepnoteServerStarter, IExtension
      */
     private async cleanupOrphanedProcesses(): Promise<void> {
         try {
+            const startTime = Date.now();
             logger.info('Checking for orphaned deepnote-toolkit processes...');
 
             // First, clean up any orphaned processes using known ports
-            // This catches LSP servers (2087) and Jupyter servers (8888+) that may be stuck
+            // This catches LSP servers (2087) and Jupyter servers (8888-8895) that may be stuck
             await this.cleanupProcessesByPort(2087); // Python LSP server
-            await this.cleanupProcessesByPort(8888); // Default Jupyter port
+
+            // Scan common Jupyter port range (8888-8895)
+            // Jupyter typically uses 8888 but will increment if that port is busy
+            for (let port = 8888; port <= 8895; port++) {
+                await this.cleanupProcessesByPort(port);
+            }
+
+            const portCleanupTime = Date.now() - startTime;
+            logger.debug(`Port-based cleanup completed in ${portCleanupTime}ms`);
 
             const processService = await this.processServiceFactory.create(undefined);