feat(editor): F4.6b the command line on a computer's desktop

A new oracle, TerminalWindowRun, types into Java's own command line
window: the window writes each line after its prompt, takes a blank
line, cls, reset and exit itself, keeps the lines for the arrow keys,
and keeps its text, history and working directory over a stop and a
start.

The room now holds a command line window per computer for everyone
(TerminalWindow), kept over stops; the protocol carries its lines and
the one way to read them (terminalScreen); the core goes on in the
working directory of the run before (continueIn). The desktop opens
programs in Java's frame, and the command line works with keyboard and
finger: grey on black, the prompt hidden while a command runs, history,
chips for the commands, Ctrl+C. The room's failure is now tested in the
browser.

Fixed: the room handed the engine the wall clock with fractions of a
millisecond, and a ping hung after its first timeout. The engine and
the room count whole milliseconds, as Java's clock does.

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

tools/java-oracle/README.md

@@ -1239,3 +1239,29 @@ Gemessen (03.10.2026):
   Karte; ohne Karte behält der Router kein Gateway (`setStandardGateway`
   schreibt es in die Karten, `getStandardGateway` liest `null`).
 
+### Das Fenster der Befehlszeile (F4.6b)
+
+`TerminalWindowRun` öffnet Javas `GUIApplicationTerminalWindow` auf einem
+`GUIDesktopPanel` eines Rechners ohne Netz, gibt Tasten direkt an den
+Tastenhörer des Eingabefelds (Enter, Pfeil hoch/runter), stoppt und startet
+das System einmal (`beenden`, `starten`, wie ein Moduswechsel) und schreibt
+nach jeder Taste Text, Prompt, ob er sichtbar ist, und die Eingabezeile
+(`packages/sim/test/terminalWindow.java.json`).
+
+Gemessen (03.10.2026):
+
+* Eine leere Zeile, auch nur aus Leerzeichen (`StringUtils.isBlank`), gibt
+  „␣␣\n“; jede andere Zeile steht danach als „\n“ + Prompt + Zeile + „\n“
+  im Fenster, auch `cls`, `reset` und `exit`, bevor das Fenster sie selbst
+  erledigt.
+* `cls`/`reset` zeigen wieder den Startbildschirm; `exit` schließt das
+  Fenster, sein Text bleibt.
+* Pfeil hoch geht durch alle eingegebenen Zeilen zurück (leere nicht),
+  runter vor, unter der neuesten steht eine leere Zeile; über die Enden
+  hinaus bleibt es stehen.
+* Der Prompt folgt dem Arbeitsverzeichnis, nachgeführt, wenn ein Befehl
+  fertig ist (`cd dir` → „/dir> “).
+* Nach Stopp und Start bleiben Text, Verlauf **und** Arbeitsverzeichnis:
+  Javas Terminal setzt den Ordner nur bei der Installation
+  (`setSystemSoftware`), und das Fenster ist dasselbe Objekt.
+

tools/java-oracle/run.sh

@@ -21,7 +21,7 @@ if [ ! -f "$upstream/target/filius.jar" ]; then
 fi
 classpath="$upstream/target/filius.jar:$upstream/target/lib/*"
 mkdir -p "$here/.build"
-javac -encoding UTF-8 -d "$here/.build" -cp "$classpath" "$here/src/FlsOracle.java" "$here/src/GetterDefaults.java" "$here/src/IpCheckCases.java" "$here/src/DnsHostsCases.java" "$here/src/EmailFileCases.java" "$here/src/BeansDump.java" "$here/src/Base64Cases.java" "$here/src/ScenarioNetwork.java" "$here/src/DhcpRun.java" "$here/src/TcpRun.java" "$here/src/DnsRun.java" "$here/src/ArpRun.java" "$here/src/RipRun.java" "$here/src/NatRun.java" "$here/src/WlanRun.java" "$here/src/ExampleRun.java" "$here/src/EchoRun.java" "$here/src/WebRun.java" "$here/src/RouterWebRun.java" "$here/src/KonfigCases.java" "$here/src/EmailRun.java" "$here/src/MailCases.java" "$here/src/EmailClientRun.java" "$here/src/TerminalCases.java" "$here/src/TerminalRun.java" "$here/src/FileCases.java" "$here/src/GnutellaRun.java" "$here/src/NewDeviceRun.java" "$here/src/SheetRun.java"
+javac -encoding UTF-8 -d "$here/.build" -cp "$classpath" "$here/src/FlsOracle.java" "$here/src/GetterDefaults.java" "$here/src/IpCheckCases.java" "$here/src/DnsHostsCases.java" "$here/src/EmailFileCases.java" "$here/src/BeansDump.java" "$here/src/Base64Cases.java" "$here/src/ScenarioNetwork.java" "$here/src/DhcpRun.java" "$here/src/TcpRun.java" "$here/src/DnsRun.java" "$here/src/ArpRun.java" "$here/src/RipRun.java" "$here/src/NatRun.java" "$here/src/WlanRun.java" "$here/src/ExampleRun.java" "$here/src/EchoRun.java" "$here/src/WebRun.java" "$here/src/RouterWebRun.java" "$here/src/KonfigCases.java" "$here/src/EmailRun.java" "$here/src/MailCases.java" "$here/src/EmailClientRun.java" "$here/src/TerminalCases.java" "$here/src/TerminalRun.java" "$here/src/FileCases.java" "$here/src/GnutellaRun.java" "$here/src/NewDeviceRun.java" "$here/src/SheetRun.java" "$here/src/TerminalWindowRun.java"
 # FILIUS writes its settings below $HOME; keep them out of the real one.
 mkdir -p "$here/.build/home"
 # Removed first: a crashed run must not leave the previous result standing.
@@ -337,6 +337,14 @@ HOME="$here/.build/home" xvfb-run -a java -cp "$classpath:$here/.build" SheetRun
     "$root/packages/doc/test/sheet.cases.txt" "$output" 2>&1 | grep -v 'logback\|^$' || true
 test -s "$output"
 
+# FILIUS' command line window as it shows what is typed into it, key by key,
+# over a stop and a start (TerminalWindowRun): the room's window
+# (packages/sim/test/terminalWindow.test.ts).
+output="$root/packages/sim/test/terminalWindow.java.json"
+rm -f "$output"
+HOME="$here/.build/home" xvfb-run -a java -Duser.language=de -Duser.country=DE -cp "$classpath:$here/.build" TerminalWindowRun "$output" 2>&1 | grep -v 'logback\|^$' || true
+test -s "$output"
+
 # FILIUS' own examples as Java FILIUS runs them, opened and started as FILIUS
 # does (ExampleRun): the acceptance of F2 (packages/fls/test/examplesJava.test.ts)
 # and the classics of F3 (web, email, gnutella; packages/fls/test/classicsJava.test.ts).

tools/java-oracle/src/TerminalWindowRun.java

@@ -0,0 +1,108 @@
+// Types into FILIUS' own command line window (GUIApplicationTerminalWindow on
+// a GUIDesktopPanel) of a computer without a network, key by key as its key
+// listener hears them, and writes after each key what the window shows: its
+// text, its prompt and whether the prompt is shown, the input line. Then the
+// simulation is stopped and started again (beenden, starten), as a change of
+// mode does, and the window and the working directory are read again: the
+// reference for the editor's command line window (packages/sim/test/
+// terminalWindow.test.ts).
+//
+// Usage: java -cp filius.jar:lib/*:classes TerminalWindowRun <output json>
+
+import filius.gui.anwendungssicht.GUIApplicationTerminalWindow;
+import filius.gui.anwendungssicht.GUIDesktopPanel;
+import filius.hardware.knoten.Rechner;
+import filius.software.system.Betriebssystem;
+
+import java.awt.event.KeyEvent;
+import java.awt.event.KeyListener;
+import java.io.FileOutputStream;
+import java.lang.reflect.Field;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import javax.swing.JLabel;
+import javax.swing.JTextArea;
+import javax.swing.JTextField;
+
+public class TerminalWindowRun {
+    static final String TERMINAL = "filius.software.lokal.Terminal";
+
+    static Object field(Object owner, String name) throws Exception {
+        Field field = GUIApplicationTerminalWindow.class.getDeclaredField(name);
+        field.setAccessible(true);
+        return field.get(owner);
+    }
+
+    static Map<String, Object> shown(GUIApplicationTerminalWindow window, String step) throws Exception {
+        Map<String, Object> result = new LinkedHashMap<>();
+        result.put("step", step);
+        result.put("text", ((JTextArea) field(window, "terminalField")).getText());
+        JLabel label = (JLabel) field(window, "inputLabel");
+        result.put("prompt", label.getText());
+        result.put("promptShown", label.isVisible());
+        result.put("input", ((JTextField) field(window, "inputField")).getText());
+        return result;
+    }
+
+    static void press(JTextField input, int key, int modifiers) {
+        KeyEvent event = new KeyEvent(input, KeyEvent.KEY_PRESSED, System.currentTimeMillis(), modifiers, key, KeyEvent.CHAR_UNDEFINED);
+        for (KeyListener listener : input.getKeyListeners()) listener.keyPressed(event);
+    }
+
+    /** Waits until the program has answered: the prompt is shown again (or a second passed). */
+    static void settle(GUIApplicationTerminalWindow window) throws Exception {
+        JLabel label = (JLabel) field(window, "inputLabel");
+        for (int waited = 0; waited < 2000 && !label.isVisible(); waited += 20) Thread.sleep(20);
+        Thread.sleep(200);
+    }
+
+    public static void main(String[] args) throws Exception {
+        try {
+            run(args);
+        } catch (Throwable error) {
+            error.printStackTrace();
+            System.exit(1);
+        }
+        System.exit(0);
+    }
+
+    static void run(String[] args) throws Exception {
+        Rechner host = new Rechner();
+        Betriebssystem system = (Betriebssystem) host.getSystemSoftware();
+        system.installApp(TERMINAL, true);
+        system.starten();
+        GUIDesktopPanel desktop = new GUIDesktopPanel(system);
+        GUIApplicationTerminalWindow window = (GUIApplicationTerminalWindow) desktop.starteAnwendung(TERMINAL);
+        JTextField input = (JTextField) field(window, "inputField");
+        List<Object> steps = new ArrayList<>();
+        steps.add(shown(window, "open"));
+        // A line typed and entered ("type:<line>"), a key ("up", "down", "ctrl+c"), a stop and start ("restart").
+        String[] keys = { "enter:", "enter:   ", "enter:pwd", "enter:mkdir dir", "enter:cd dir", "enter:pwd", "enter:nosuchcommand", "up", "up", "up", "down", "down", "down",
+                "enter:cls", "enter:ls", "restart", "enter:pwd", "up", "enter:exit" };
+        for (String key : keys) {
+            if (key.startsWith("enter:")) {
+                input.setText(key.substring("enter:".length()));
+                press(input, KeyEvent.VK_ENTER, 0);
+                settle(window);
+            } else if (key.equals("up")) {
+                press(input, KeyEvent.VK_UP, 0);
+            } else if (key.equals("down")) {
+                press(input, KeyEvent.VK_DOWN, 0);
+            } else if (key.equals("restart")) {
+                system.beenden();
+                system.starten();
+                Thread.sleep(300);
+            }
+            steps.add(shown(window, key));
+        }
+        Map<String, Object> output = new LinkedHashMap<>();
+        output.put("steps", steps);
+        try (FileOutputStream out = new FileOutputStream(args[0])) {
+            out.write((FlsOracle.Json.write(output, "") + "\n").getBytes(StandardCharsets.UTF_8));
+        }
+        System.out.println("terminal window steps: " + steps.size());
+    }
+}