feat(core): traceroute and tcpdump after Java, measured against Java

TerminalRun adds nine stories: traceroute in the LAN, through the router,
unreachable, without a route, to no one, to the host itself, errors and
Ctrl+C; tcpdump on two hosts. traceroute counts failures across hops as
Java does and takes an error that carries its probe; tcpdump tells each
frame's highest capture row with its time of day, at once.

Departures from Java: traceroute tells its summary before the end mark
(Java after it, where its window shows no text) and calls a host at the
20th hop reached. arpsend is not built.

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

packages/core/src/runtime/engine.ts

@@ -4203,7 +4203,6 @@ export class NetworkRuntimeEngine {
     this.sendEthernetFrame(nodeId, networkInterface.portId, frame);
   }
 
-
   private earliestDeadline(filter: (kind: ScheduledEventKind) => boolean): number | undefined {
     let earliest: number | undefined;
     for (const event of this.stateValue.pendingEvents) {
@@ -4714,6 +4713,11 @@ export class NetworkRuntimeEngine {
     return result;
   }
 
+  /** The time of day (wallClock) when the simulation was at `milliseconds`, counted back from now. */
+  wallTime(milliseconds: number): number {
+    return this.wallClock() - (this.stateValue.currentTimeMilliseconds - milliseconds);
+  }
+
   /** The first ICMP identifier of a command line (Terminal.setIdentifier: new Random().nextInt(43) * 23). */
   drawIcmpIdentifier(): number {
     return this.icmpIdentifierRandom.nextInt(43) * 23;