feat: complete pre-launch audit — frontend polish, churn prevention, login history, financial reports, configurable checkout

Includes all work from phases 6-9+ and frontend polish rounds 1 & 2:

- Login history with device trust, new device notifications, session management
- Churn prevention: cancellation surveys, winback campaigns with email sequences
- Financial reports: revenue, P&L, tax, aging, refund, subscription reports with PDF/CSV/JSON export
- Configurable checkout: plan config groups/options, build-your-own VPS
- Frontend polish: fix broken legal links, add SEO meta tags, favicon, font display=swap,
  Head titles on all 14 marketing pages, mobile responsive fixes, AuthLayout legal footer,
  remove false 24/7 claims, hide empty stats, correct uptime SLA to 99.9%,
  GameServers notify buttons linked to /contact, 301 redirects for /terms and /privacy
- WHMCS migration scripts
- Update legal page effective dates to March 16, 2026

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

scripts/whmcs-migrate/.gitignore

@@ -0,0 +1,6 @@
+/vendor/
+.env
+state/
+logs/
+exports/
+composer.lock