feat: Quiet Luxury design system + Pipeline (ex-Lead) redesign

- Design system foundations: Plus Jakarta Sans font, shadow-card/radius
  tokens in @theme, design-reference/DESIGN-SYSTEM.md with component inventory
- Collapsible admin shell (AdminShell): smooth w-64<->w-20 sidebar, new top
  header with "Admin" + avatar placeholder, localStorage-persisted state
- Rename route /admin/leads -> /admin/pipeline (redirect stubs preserved),
  nav label Lead -> Pipeline; DB table unchanged
- Reusable primitives: StatusBadge, SearchInput, SegmentedToggle (dual-theme)
- Luxury restyle of lead table, kanban (6 stages + @dnd-kit intact), PageHeader
- Tokenize editable-cell / option-multi-select for dark-mode legibility

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/admin/leads/[id]/page.tsx

@@ -1,40 +1,12 @@
-import { notFound } from "next/navigation";
-import { getActivityLog, getUpcomingReminders, getTranscripts } from "@/lib/lead-service";
-import {
-  getLeadByIdWithTags,
-  getLeadFieldOptions,
-  getClientIdFromLead,
-} from "@/lib/admin-queries";
-import { LeadDetail } from "@/components/admin/leads/LeadDetail";
+import { redirect } from "next/navigation";
 
-export default async function LeadDetailPage({ params }: { params: Promise<{ id: string }> }) {
+// Legacy route — Lead was renamed to Pipeline. Kept as a redirect stub so
+// existing links/bookmarks to /admin/leads/<id> don't break.
+export default async function LeadDetailRedirectPage({
+  params,
+}: {
+  params: Promise<{ id: string }>;
+}) {
   const { id } = await params;
-
-  const [lead, options, convertedClientId] = await Promise.all([
-    getLeadByIdWithTags(id),
-    getLeadFieldOptions(),
-    getClientIdFromLead(id),
-  ]);
-
-  if (!lead) {
-    notFound();
-  }
-
-  const [activities, reminders, transcripts] = await Promise.all([
-    getActivityLog(id),
-    getUpcomingReminders(id),
-    getTranscripts(id),
-  ]);
-
-  return (
-    <LeadDetail
-      lead={lead}
-      activities={activities}
-      reminders={reminders}
-      tags={lead.tags}
-      tagOptions={options.tags}
-      transcripts={transcripts}
-      convertedClientId={convertedClientId}
-    />
-  );
+  redirect(`/admin/pipeline/${id}`);
 }