Major product upgrade: landing page, scanning UI, admin panel, working reports

Frontend:
- New public marketing landing page at / (hero, features, stats, how-it-works, CTA)
- New /scans page surfacing the scanning engine: asset health grid, one-click
  full scan, live scanner findings feed, 24h stats
- New /admin panel (was a 404 from the sidebar): audit report generation and
  instant PDF snapshot download
- Reports page: now visible to all roles, working PDF downloads, posture
  snapshot export for IT/admin
- Findings page: full-text search, sorting (severity/newest/title), severity
  count chips, CSV export
- Dashboard: scan activity strip, Run Scan + Export PDF quick actions
- Footprint page: summary stat cards
- api.ts: scanning, reports, and PDF download endpoints + types;
  fixed missing resolution_note on Finding type
- Removed unsupported eslint key from next.config.ts

Backend:
- Audit reports: list/get/PDF now open to executives and IT admins with strict
  tenant isolation (was trustos_admin-only, leaving tenants unable to see
  their own reports); PDF snapshot open to IT admins; generation stays
  admin-only

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/next.config.ts

@@ -9,9 +9,6 @@ const nextConfig: NextConfig = {
       },
     ];
   },
-  eslint: {
-    ignoreDuringBuilds: true,
-  },
 };
 
 export default nextConfig;