Don't collapse ambiguous senders to imply an indirect link betwen repeaters

frontend/src/networkGraph/packetNetworkGraph.ts

@@ -710,13 +710,22 @@ function projectCanonicalPathWithAliases(
   repeaterAliases: Map<string, string>
 ): ProjectedPacketNetworkPath {
   const projected = compactPathSteps(
-    canonicalPath.map((nodeId) => ({
-      nodeId: isPacketNetworkNodeVisible(state.nodes.get(nodeId), visibility)
-        ? (repeaterAliases.get(nodeId) ?? nodeId)
-        : null,
-      markHiddenLinkWhenOmitted: true,
-      hiddenLabel: null,
-    }))
+    canonicalPath.map((nodeId, index) => {
+      const node = state.nodes.get(nodeId);
+      const visible = isPacketNetworkNodeVisible(node, visibility);
+      return {
+        nodeId: visible ? (repeaterAliases.get(nodeId) ?? nodeId) : null,
+        // Only hidden repeater hops should imply a bridged dashed segment.
+        // Hidden sender/recipient endpoints should disappear with their own edge.
+        markHiddenLinkWhenOmitted:
+          !visible &&
+          !!node &&
+          node.type === 'repeater' &&
+          index > 0 &&
+          index < canonicalPath.length - 1,
+        hiddenLabel: null,
+      };
+    })
   );
 
   return {

frontend/src/test/packetNetworkGraph.test.ts

@@ -9,6 +9,7 @@ import {
   projectPacketNetwork,
   snapshotNeighborIds,
 } from '../networkGraph/packetNetworkGraph';
+import { buildLinkKey } from '../utils/visualizerUtils';
 import type { Contact, RadioConfig, RawPacket } from '../types';
 import { CONTACT_TYPE_REPEATER } from '../types';
 
@@ -181,6 +182,63 @@ describe('packetNetworkGraph', () => {
     expect(projection.links.get('565656565656->self')?.hasDirectObservation).toBe(true);
   });
 
+  it('does not bridge across hidden ambiguous sender endpoints', () => {
+    const selfKey = 'ffffffffffff0000000000000000000000000000000000000000000000000000';
+    const repeaterOneKey = '1111111111110000000000000000000000000000000000000000000000000000';
+    const repeaterTwoKey = '2222222222220000000000000000000000000000000000000000000000000000';
+    const repeaterThreeKey = '3333333333330000000000000000000000000000000000000000000000000000';
+    const repeaterFourKey = '4444444444440000000000000000000000000000000000000000000000000000';
+
+    packetFixtures.set('dm-hidden-ambiguous-sender-a', {
+      payloadType: PayloadType.TextMessage,
+      messageHash: 'dm-hidden-ambiguous-sender-a',
+      pathBytes: ['111111111111', '222222222222'],
+      srcHash: '32',
+      dstHash: 'ffffffffffff',
+      advertPubkey: null,
+      groupTextSender: null,
+      anonRequestPubkey: null,
+    });
+    packetFixtures.set('dm-hidden-ambiguous-sender-b', {
+      payloadType: PayloadType.TextMessage,
+      messageHash: 'dm-hidden-ambiguous-sender-b',
+      pathBytes: ['333333333333', '444444444444'],
+      srcHash: '32',
+      dstHash: 'ffffffffffff',
+      advertPubkey: null,
+      groupTextSender: null,
+      anonRequestPubkey: null,
+    });
+
+    const state = createPacketNetworkState('Me');
+    const context = buildPacketNetworkContext({
+      contacts: [
+        createContact(repeaterOneKey, 'Relay 1', CONTACT_TYPE_REPEATER),
+        createContact(repeaterTwoKey, 'Relay 2', CONTACT_TYPE_REPEATER),
+        createContact(repeaterThreeKey, 'Relay 3', CONTACT_TYPE_REPEATER),
+        createContact(repeaterFourKey, 'Relay 4', CONTACT_TYPE_REPEATER),
+      ],
+      config: createConfig(selfKey),
+      repeaterAdvertPaths: [],
+      splitAmbiguousByTraffic: false,
+      useAdvertPathHints: false,
+    });
+
+    ingestPacketIntoPacketNetwork(state, context, createPacket('dm-hidden-ambiguous-sender-a'));
+    ingestPacketIntoPacketNetwork(state, context, createPacket('dm-hidden-ambiguous-sender-b'));
+
+    const projection = projectPacketNetwork(state, {
+      showAmbiguousNodes: false,
+      showAmbiguousPaths: true,
+      collapseLikelyKnownSiblingRepeaters: true,
+    });
+
+    expect(projection.links.has(buildLinkKey('111111111111', '222222222222'))).toBe(true);
+    expect(projection.links.has(buildLinkKey('333333333333', '444444444444'))).toBe(true);
+    expect(projection.links.has(buildLinkKey('111111111111', '333333333333'))).toBe(false);
+    expect(projection.links.has(buildLinkKey('222222222222', '444444444444'))).toBe(false);
+  });
+
   it('does not add a DM recipient node from destination metadata alone', () => {
     const selfKey = 'ffffffffffff0000000000000000000000000000000000000000000000000000';
     const aliceKey = 'aaaaaaaaaaaa0000000000000000000000000000000000000000000000000000';