feat(editor): F4.5e a router's connections in the device sheet

SheetRun now clicks through Java's JConnectionsDialog with a router, a
computer and a switch cabled in the GUIContainer: a click marks a card,
the same click unmarks it, another card swaps the cables or moves the
one; "+" adds 192.168.0.10/24 up to eight cards, "-" removes the last
card with its cable down to none, and a router without a card keeps no
gateway.

The document adds, removes and swaps a router's cards (the same cables,
the same devices), Java's click logic is one function for the test and
the page, and the sheet names the address at a cable's far end. The
page "Verbindungen verwalten" shows Java's RJ45 buttons in Java's
colours with each card's far end below. Not adopted: the last card
stays. A card tab or a mark whose card is undone away falls back.

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

packages/doc/src/sheet.ts

@@ -88,8 +88,13 @@ export interface InterfaceSheet {
   readonly ipAddress: string;
   readonly subnetMask: string;
   readonly macAddress: string;
-  /** The device at the other end of its cable (its label, as Java names it) and the cable; null without one. */
-  readonly connected: { readonly device: string; readonly link: string } | null;
+  /**
+   * The device at the other end of its cable (its label, as Java names it),
+   * the address of the card the cable plugs into there (a computer's, a
+   * router's; null for a switch or a modem, which have none) and the cable;
+   * null without one.
+   */
+  readonly connected: { readonly device: string; readonly address: string | null; readonly link: string } | null;
 }
 
 /** A router's or home router's firewall as Java's dialog shows it (JFirewallDialog). */
@@ -142,6 +147,22 @@ const setting = (node: Y.Map<unknown>, key: string) => settingsOf(node).get(key)
 
 const text = (map: Y.Map<unknown> | undefined, key: string) => (map?.get(key) as string | undefined) ?? '';
 
+/** The address of a device's card at a port, as Java's NetzwerkInterface holds it; null for a device without cards (InternetKnoten). */
+function cardAddress(node: Y.Map<unknown>, portId: string): string | null {
+  switch (node.get('kind') as NodeKind) {
+    case 'pc':
+    case 'notebook':
+      return text(setting(node, 'device'), 'ipAddress');
+    case 'router':
+    case 'gateway': {
+      const port = (node.get('ports') as Y.Array<Y.Map<unknown>>).toArray().find((each) => each.get('id') === portId);
+      return text(port?.get('config') as Y.Map<unknown> | undefined, 'ipAddress');
+    }
+    default:
+      return null;
+  }
+}
+
 /** A router's or home router's cards, each with what its cable joins. */
 function interfacesOf(doc: Y.Doc, id: string, node: Y.Map<unknown>): InterfaceSheet[] {
   const all = doc.getMap<Y.Map<unknown>>(ROOTS.nodes);
@@ -150,14 +171,14 @@ function interfacesOf(doc: Y.Doc, id: string, node: Y.Map<unknown>): InterfaceSh
     const portId = port.get('id') as string;
     const config = port.get('config') as Y.Map<unknown> | undefined;
     const cable = links.find(([, link]) => (link.get('sourceNode') === id && link.get('sourcePort') === portId) || (link.get('targetNode') === id && link.get('targetPort') === portId));
-    const other =
-      cable === undefined ? undefined : all.get((cable[1].get('sourceNode') === id && cable[1].get('sourcePort') === portId ? cable[1].get('targetNode') : cable[1].get('sourceNode')) as string);
+    const near = cable !== undefined && cable[1].get('sourceNode') === id && cable[1].get('sourcePort') === portId;
+    const other = cable === undefined ? undefined : all.get(cable[1].get(near ? 'targetNode' : 'sourceNode') as string);
     return {
       portId,
       ipAddress: text(config, 'ipAddress'),
       subnetMask: text(config, 'subnetMask'),
       macAddress: (port.get('mac') as string | undefined) ?? stableGeneratedMacAddress(portId),
-      connected: cable === undefined || other === undefined ? null : { device: nodeLabel(other), link: cable[0] },
+      connected: cable === undefined || other === undefined ? null : { device: nodeLabel(other), address: cardAddress(other, cable[1].get(near ? 'targetPort' : 'sourcePort') as string), link: cable[0] },
     };
   });
 }