feat(core): the command line's network commands ping, host, nslookup, arp and netstat after Java, measured against Java

TerminalRun types lines into Java's command line on terminal-net at set
times; the engine types the same lines. New in the engine: an ICMP echo
in a program's thread (the first ICMP message after the send, whatever
it is), Java's route choice, the ARP table with Java's broadcast row, DNS
in a program's thread, ICMP broadcasts of a node's own network, and an
ARP wait that ends after what else happens at that millisecond.

Departures from Java: an echo is answered from the address asked
(RFC 792), network unreachable carries the packet with its sender, ping
names the host and takes only -b before it, arp and netstat list in the
order learned, netstat lists a UDP server's listening socket only.

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

packages/core/test/terminal.test.ts

@@ -217,6 +217,11 @@ describe('the command line as Java FILIUS answers it', () => {
     const cases = javaCases(language);
     const text = (key: TerminalTextKey) => TERMINAL_TEXTS[language][key];
 
+    it(`has Java's texts (${language})`, () => {
+      const javaTexts = (JSON.parse(readFileSync(join(here, `terminal.${language}.java.json`), 'utf8')) as { texts: Record<string, string> }).texts;
+      for (const [key, value] of Object.entries(TERMINAL_TEXTS[language])) expect(value, key).toBe(javaTexts[key]);
+    });
+
     it(`corrects Java only where it errs (${language})`, () => {
       for (const [name, fix] of Object.entries(JAVA_BUGS)) {
         const javaCase = cases.find((each) => each.name === name)!;