feat(pitch-deck): admin UI for investor + financial-model management

Adds /pitch-admin dashboard with real admin accounts (bcrypt) and full
audit attribution for every state-changing action.

Backend:
- pitch_admins + pitch_admin_sessions tables (migration 002)
- pitch_audit_logs.admin_id + target_investor_id columns
- lib/admin-auth.ts: bcryptjs hashing, single-session enforcement,
  jose JWT with 'pitch-admin' audience claim, requireAdmin guard
- logAudit extended to accept admin_id and target_investor_id
- middleware.ts: gates /pitch-admin/* and /api/admin/* on the admin
  cookie (with bearer-secret fallback for CLI compatibility)
- 14 API routes under /api/admin-auth and /api/admin (login, logout,
  me, dashboard, investors[id] CRUD + resend, admins CRUD,
  fm scenarios + assumptions PATCH)
- Existing /api/admin/{invite,investors,revoke,audit-logs} migrated
  to requireAdmin and now log with admin_id + target_investor_id
- scripts/create-admin.ts CLI bootstrap (npm run admin:create)

Frontend:
- /pitch-admin/login + /pitch-admin/(authed) route group
- AdminShell with sidebar nav + StatCard + AuditLogTable components
- Dashboard with KPIs, recent logins, recent activity
- Investors list with search/filter + resend/revoke inline actions
- Investor detail with inline edit + per-investor audit timeline
- Audit log viewer with actor/action/date filters + pagination
- Financial model scenario list + per-scenario assumption editor
  (categorized, inline edit, before/after diff in audit)
- Admins management (add, deactivate, reset password)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pitch-deck/components/pitch-admin/StatCard.tsx

@@ -0,0 +1,33 @@
+import { LucideIcon } from 'lucide-react'
+
+interface StatCardProps {
+  label: string
+  value: string | number
+  icon?: LucideIcon
+  hint?: string
+  accent?: 'indigo' | 'green' | 'amber' | 'rose'
+}
+
+const ACCENTS = {
+  indigo: 'text-indigo-400 bg-indigo-500/10 border-indigo-500/20',
+  green: 'text-green-400 bg-green-500/10 border-green-500/20',
+  amber: 'text-amber-400 bg-amber-500/10 border-amber-500/20',
+  rose: 'text-rose-400 bg-rose-500/10 border-rose-500/20',
+}
+
+export default function StatCard({ label, value, icon: Icon, hint, accent = 'indigo' }: StatCardProps) {
+  return (
+    <div className="bg-white/[0.04] border border-white/[0.06] rounded-2xl p-5">
+      <div className="flex items-start justify-between mb-3">
+        <span className="text-xs font-medium text-white/50 uppercase tracking-wider">{label}</span>
+        {Icon && (
+          <div className={`w-9 h-9 rounded-lg flex items-center justify-center border ${ACCENTS[accent]}`}>
+            <Icon className="w-4 h-4" />
+          </div>
+        )}
+      </div>
+      <div className="text-3xl font-semibold text-white">{value}</div>
+      {hint && <div className="text-xs text-white/40 mt-1">{hint}</div>}
+    </div>
+  )
+}