#26 Mobile responsive:
- Hamburger button (SVG) in topbar for all three panels (admin/user/reseller)
- Sidebar overlay div for click-outside-to-close on mobile
- nova.js: DOMContentLoaded toggle handler with overlay and auto-close on nav click
- nova.css: sidebar-overlay, page-header, panel/panel-header, table, btn-success/warning/danger/secondary/xs,
badge-muted; mobile media query shows toggle, fixes stats-grid/modal/panel-header layout
#27 Custom error pages:
- /errors/404.php and /errors/500.php with NovaCPX dark theme matching panel design
- Apache ErrorDocument 400/401/403/404/500/503 for ports 8880/8881/8882 with Alias /errors
#28 API rate limiting:
- api_rate_limits table (migration 004) with per-IP per-bucket counters
- api/index.php: 10 req/min for auth endpoint, 120 req/min for all others
- Returns X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset headers
- Returns 429 Too Many Requests when exceeded; rate limit failure is non-fatal
#29 Session Manager:
- sessions.php endpoint: list/revoke/revoke-user/revoke-all
- Admin panel Sessions page: table of active sessions with user, role, IP, browser, timestamps
- Revoke single session, revoke all for user, revoke all sessions (self-evicts)
- AccountManager: auto-generate DKIM keypair + inject SPF/DKIM/DMARC DNS records on account create
- AccountManager: rotateDKIM() method for key rotation with new selector
- New dkim.php endpoint: list/view/rotate/provision DKIM keys per domain
- schema.sql: add dkim_keys table
- install.sh: install opendkim, wire into Postfix milter, fix dotfile copy (. vs *), fix config.ini permissions (root:www-data 640), copy VERSION to web root, add opendkim to service restart
- api/index.php: fix NOVACPX_ROOT path (was 2 levels too high), fix CORS ports (8880-8883), VERSION fallback to /opt/novacpx-src
- api/.htaccess: route all /api/* requests through index.php
- system.php: check-os-update, apply-os-update (self-healing: auto-restart downed services, restore web root if panel ports go down), check-novacpx-update, apply-novacpx-update (PHP syntax validation before deploy, backup + restore on failure)
- admin.js: Updates page now shows both NovaCPX panel updates and OS package upgrades in one section; sidebar badge shows combined count
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>