feat(editor): the simulation's properties in a sheet of their own, with a restart for everyone

Who started the simulation, "Pakete verwerfen" and the dropped packets move
from the toolbar into a properties sheet beside the surface. New in it: restart
the simulation, after asking. The room learns a restart message: stopped as by
stop, every capture, dropped frame and program window emptied, started anew
and named after who restarted; refused for readers and frozen projects, logged,
and waiting for asked blobs like a start.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/sim/src/room.ts

@@ -393,6 +393,9 @@ export class SimulationRoom {
       case 'stop':
         this.stop();
         return;
+      case 'restart':
+        this.restart(input.language, client.name);
+        return;
       case 'drop':
         if (this.mode !== 'simulation') {
           client.send(message({ kind: 'error', code: 'notRunning' }));
@@ -475,6 +478,28 @@ export class SimulationRoom {
     this.flush([...this.clients.values()], false);
   }
 
+  /**
+   * Starts the simulation anew, as though nothing had run before: stopped as
+   * by stop (what the devices wrote stays in the document), every card's
+   * capture, the dropped frames and every program window emptied — Java's
+   * outlive a stop — and started. Each watcher gets its lists and windows
+   * anew, from their beginning (the dropped frames start does anew anyway; a
+   * view is compared, so a changed one goes out by itself).
+   */
+  restart(language?: PageLanguage, startedBy?: string): void {
+    this.stop();
+    this.engine.clearCapture();
+    // The cables light up again with the first frame, not once a card has more than before.
+    this.framesSeen.clear();
+    this.terminalWindows.clear();
+    this.browserWindows.clear();
+    for (const client of this.clients.values()) {
+      client.traceSent.clear();
+      client.appSent.clear();
+    }
+    this.start(language, startedBy);
+  }
+
   /** Lets the simulation run to the wall clock's time, then sends what came of it. */
   tick(): void {
     if (this.mode !== 'simulation') return;