Hide Infrastructure tab in portal SaaS build

The Infrastructure view isn't wired up for SaaS yet, so hide it from the
sidebar there until it is. Adds a HIDDEN_NAV_VIEWS flavor seam: core is
empty (self-hosted shows the full nav) and the portal-saas shadow hides
"infrastructure". The Sidebar filters nav entries against it.

Bring it back by emptying the set in portal-saas/components/navVisibility.

frontend/editor/src/portal-saas/components/navVisibility.test.ts

@@ -0,0 +1,10 @@
+import { describe, expect, it } from "vitest";
+
+// Resolves to the SaaS override (src/portal-saas/components) via the @portal cascade.
+import { HIDDEN_NAV_VIEWS } from "@portal/components/navVisibility";
+
+describe("navVisibility (SaaS) — hidden nav entries", () => {
+  it("hides the Infrastructure tab (not built for SaaS yet)", () => {
+    expect(HIDDEN_NAV_VIEWS.has("infrastructure")).toBe(true);
+  });
+});

frontend/editor/src/portal-saas/components/navVisibility.ts

@@ -0,0 +1,10 @@
+import type { ViewId } from "@portal/contexts/ViewContext";
+
+/**
+ * SaaS flavor: the Infrastructure tab isn't built for SaaS yet, so hide it from
+ * the sidebar until it is. Drop the entry here (or empty the set) to bring it
+ * back.
+ */
+export const HIDDEN_NAV_VIEWS: ReadonlySet<ViewId> = new Set<ViewId>([
+  "infrastructure",
+]);

frontend/editor/src/portal/components/Sidebar.tsx

@@ -7,6 +7,7 @@ import { useTier } from "@portal/contexts/TierContext";
 import { useTheme } from "@portal/contexts/ThemeContext";
 import { useUI } from "@portal/contexts/UIContext";
 import { LinkAccountFooterItem } from "@portal/components/LinkAccountFooterItem";
+import { HIDDEN_NAV_VIEWS } from "@portal/components/navVisibility";
 import { useAsync } from "@portal/hooks/useAsync";
 import { fetchHomeKpis, type KpiEntry } from "@portal/api/home";
 import { EDITOR_URL, EDITOR_IS_SAME_APP } from "@portal/auth/editorUrl";
@@ -129,16 +130,18 @@ export function Sidebar() {
   // a takeover modal (matching the marketing prototype).
 
   function renderGroup(entries: NavEntry[]) {
-    return entries.map((entry) => (
-      <NavItem
-        key={entry.id}
-        id={entry.id}
-        label={t(`portal.nav.${entry.id}`)}
-        icon={entry.icon}
-        isActive={activeView === entry.id}
-        onClick={(id) => setActiveView(id as ViewId)}
-      />
-    ));
+    return entries
+      .filter((entry) => !HIDDEN_NAV_VIEWS.has(entry.id))
+      .map((entry) => (
+        <NavItem
+          key={entry.id}
+          id={entry.id}
+          label={t(`portal.nav.${entry.id}`)}
+          icon={entry.icon}
+          isActive={activeView === entry.id}
+          onClick={(id) => setActiveView(id as ViewId)}
+        />
+      ));
   }
 
   return (

frontend/editor/src/portal/components/navVisibility.ts

@@ -0,0 +1,8 @@
+import type { ViewId } from "@portal/contexts/ViewContext";
+
+/**
+ * Nav entries the sidebar should hide for the current build flavor. Self-hosted
+ * shows the full nav, so this is empty. The SaaS build shadows this file to hide
+ * views that aren't wired up there yet (see portal-saas/components/navVisibility).
+ */
+export const HIDDEN_NAV_VIEWS: ReadonlySet<ViewId> = new Set();