fix(playlist): cover the generic-URL fallback in the multi-MAC portal ambiguity guard

The round-2 guard judged ambiguity over portal-shaped URLs only, while the
portal picker falls back to a generic URL when no shaped one exists — two
root-URL panels with several MACs still cross-paired through that fallback.
The guard now inspects the exact pool the picker draws from.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JE1De2dfyRZMYh4H2iGXb4

libs/shared/interfaces/src/lib/provider-import-detection.util.spec.ts

@@ -699,6 +699,26 @@ describe('detectProviderImportCandidates', () => {
             }
         });
 
+        it('treats several MACs with generic URLs on different hosts as ambiguous too', () => {
+            // Without portal-shaped URLs the picker falls back to a generic
+            // URL — the ambiguity guard must cover that pool as well, or two
+            // root-URL panels would still cross-pair through the fallback.
+            const candidates = detectProviderImportCandidates(
+                [
+                    'http://panel-a.example.com',
+                    'MAC: 00:1A:79:AA:AA:AA',
+                    'http://panel-b.example.com',
+                    'MAC: 00:1A:79:BB:BB:BB',
+                ].join('\n')
+            );
+
+            const stalker = only(candidates, 'stalker');
+            expect(stalker).toHaveLength(2);
+            for (const candidate of stalker) {
+                expect(candidate.portalUrl).toBeUndefined();
+            }
+        });
+
         it('surfaces every MAC of a long multi-account list', () => {
             const macs = Array.from(
                 { length: 6 },

libs/shared/interfaces/src/lib/provider-import-detection.util.ts

@@ -115,18 +115,26 @@ export function detectProviderImportCandidates(
     // label belongs to — and a device ID submitted with the wrong MAC is
     // pinned by the portal permanently. Multi-MAC candidates therefore carry
     // portal + MAC only, and the user supplies identity per account.
-    // Several MACs meeting portal-shaped URLs on DIFFERENT hosts is two
+    // Several MACs meeting portal candidates on DIFFERENT hosts is two
     // accounts from two panels in one paste — there is no deterministic way
     // to say which MAC belongs to which portal, so those candidates carry the
     // MAC alone instead of prefilling half of them with the wrong panel.
-    // Same-host URL pairs (the Real/Panel lines of scanner dumps) stay
-    // unambiguous, as does one portal shared by a whole MAC list.
-    const stalkerHosts = new Set(
-        urls
-            .filter((url) => url.role === 'stalker')
-            .map((url) => url.parsed.hostname)
-    );
-    const portalAmbiguous = macs.length > 1 && stalkerHosts.size > 1;
+    // The ambiguity is judged over the POOL `pickStalkerPortalUrl` would
+    // actually draw from: portal-shaped URLs when any exist, otherwise the
+    // generic-URL fallback — a guard on the shaped pool alone would let two
+    // root-URL panels slip through the fallback door. A single labeled
+    // "Portal:" line, same-host Real/Panel pairs, and one portal shared by a
+    // whole MAC list stay unambiguous.
+    const shapedPortals = urls.filter((url) => url.role === 'stalker');
+    const portalPool =
+        shapedPortals.length > 0
+            ? shapedPortals
+            : labeledHostUrl(labeled) !== undefined
+              ? []
+              : urls.filter((url) => url.role === 'generic');
+    const portalAmbiguous =
+        macs.length > 1 &&
+        new Set(portalPool.map((url) => url.parsed.hostname)).size > 1;
     const portal = portalAmbiguous
         ? null
         : pickStalkerPortalUrl(urls, labeled);