fix(api): kill currentPortId persist race + dedupe admin/ports stampede

The dashboard and residential interest smoke tests were intermittently
failing with the page rendering empty/skeleton state. Root causes:

1. ui-store persisted currentPortId/Slug, but those are URL-derived state.
   After login lands on /<first-port-by-name>/dashboard, localStorage holds
   that port. Hard-navigating to /port-nimara/... rehydrated the store with
   the stale id, and useQuery fired with the wrong port before
   PortProvider's URL-sync useEffect could correct it. Drop both fields
   from partialize — PortProvider re-derives them from the route every
   navigation.

2. apiFetch's slug-to-port fallback fired N parallel /api/v1/admin/ports
   calls when N components mounted simultaneously with an empty store.
   Dedupe in-flight lookups so a stampede collapses into one round-trip.

Also tightened four flaky smoke tests that depended on a fixed 3s wait or
non-waiting isVisible({timeout}) — replaced with expect(...).toBeVisible
or expect.poll so they handle dev-mode JIT cold-start delays cleanly.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/api/client.ts

@@ -10,21 +10,33 @@ export interface ApiFetchOptions extends Omit<RequestInit, 'body'> {
  *  Avoids re-fetching `/api/v1/admin/ports` on every request when the Zustand
  *  store hasn't hydrated yet (fresh browser context, e2e tests, hard reload). */
 const slugToIdCache = new Map<string, string>();
+/** Dedupe in-flight admin/ports lookups so a stampede of parallel apiFetch
+ *  calls (typical on dashboard mount) collapses into a single network round-
+ *  trip instead of N. */
+let inFlightPortsLookup: Promise<Array<{ id: string; slug: string }> | null> | null = null;
 
 async function resolvePortIdFromSlug(slug: string): Promise<string | null> {
   const cached = slugToIdCache.get(slug);
   if (cached) return cached;
-  try {
-    const res = await fetch('/api/v1/admin/ports', { credentials: 'include' });
-    if (!res.ok) return null;
-    const body = (await res.json()) as { data?: Array<{ id: string; slug: string }> };
-    const port = body.data?.find((p) => p.slug === slug);
-    if (!port) return null;
-    slugToIdCache.set(slug, port.id);
-    return port.id;
-  } catch {
-    return null;
+  if (!inFlightPortsLookup) {
+    inFlightPortsLookup = (async () => {
+      try {
+        const res = await fetch('/api/v1/admin/ports', { credentials: 'include' });
+        if (!res.ok) return null;
+        const body = (await res.json()) as { data?: Array<{ id: string; slug: string }> };
+        return body.data ?? null;
+      } catch {
+        return null;
+      }
+    })().finally(() => {
+      inFlightPortsLookup = null;
+    });
   }
+  const ports = await inFlightPortsLookup;
+  const port = ports?.find((p) => p.slug === slug);
+  if (!port) return null;
+  slugToIdCache.set(slug, port.id);
+  return port.id;
 }
 
 /**