Move tenant dashboard routes under /dashboard/ prefix

- Update App.tsx routes to use /dashboard/ prefix for all business user routes
- Add redirect from / to /dashboard for authenticated business users
- Update Sidebar.tsx navigation links with /dashboard/ prefix
- Update SettingsLayout.tsx settings navigation paths
- Update all help pages with /dashboard/help/ routes
- Update navigate() calls in components:
  - TrialBanner, PaymentSettingsSection, NotificationDropdown
  - BusinessLayout, UpgradePrompt, QuotaWarningBanner
  - QuotaOverageModal, OpenTicketsWidget, CreatePlugin
  - MyPlugins, PluginMarketplace, HelpTicketing
  - HelpGuide, Upgrade, TrialExpired
  - CustomDomainsSettings, QuotaSettings
- Fix hardcoded lvh.me URL in BusinessEditModal to use buildSubdomainUrl

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/pages/help/HelpResources.tsx

@@ -490,7 +490,7 @@ const HelpResources: React.FC = () => {
         <h2 className="text-xl font-semibold text-gray-900 dark:text-white mb-4">Related Features</h2>
         <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
           <Link
-            to="/help/scheduler"
+            to="/dashboard/help/scheduler"
             className="flex items-center gap-3 p-4 bg-white dark:bg-gray-800 rounded-lg border border-gray-200 dark:border-gray-700 hover:border-brand-500 transition-colors"
           >
             <Calendar size={20} className="text-brand-500" />
@@ -498,7 +498,7 @@ const HelpResources: React.FC = () => {
             <ChevronRight size={16} className="text-gray-400 ml-auto" />
           </Link>
           <Link
-            to="/help/staff"
+            to="/dashboard/help/staff"
             className="flex items-center gap-3 p-4 bg-white dark:bg-gray-800 rounded-lg border border-gray-200 dark:border-gray-700 hover:border-brand-500 transition-colors"
           >
             <Users size={20} className="text-brand-500" />
@@ -506,7 +506,7 @@ const HelpResources: React.FC = () => {
             <ChevronRight size={16} className="text-gray-400 ml-auto" />
           </Link>
           <Link
-            to="/help/settings/resource-types"
+            to="/dashboard/help/settings/resource-types"
             className="flex items-center gap-3 p-4 bg-white dark:bg-gray-800 rounded-lg border border-gray-200 dark:border-gray-700 hover:border-brand-500 transition-colors"
           >
             <Settings size={20} className="text-brand-500" />
@@ -514,7 +514,7 @@ const HelpResources: React.FC = () => {
             <ChevronRight size={16} className="text-gray-400 ml-auto" />
           </Link>
           <Link
-            to="/help/services"
+            to="/dashboard/help/services"
             className="flex items-center gap-3 p-4 bg-white dark:bg-gray-800 rounded-lg border border-gray-200 dark:border-gray-700 hover:border-brand-500 transition-colors"
           >
             <ClipboardList size={20} className="text-brand-500" />
@@ -532,7 +532,7 @@ const HelpResources: React.FC = () => {
           Our support team is ready to help with any questions about managing resources.
         </p>
         <button
-          onClick={() => navigate('/tickets')}
+          onClick={() => navigate('/dashboard/tickets')}
           className="px-6 py-2 bg-brand-600 text-white rounded-lg hover:bg-brand-700 transition-colors"
         >
           Contact Support