refactor: professional code quality audit

- Fix all TypeScript compilation errors (0 errors in src/)
- Add try/catch error handling to ALL API routes (38 handlers)
- Fix empty catch blocks (api-auth.ts now logs warnings)
- Add aria-labels to all icon-only buttons (WCAG 2.1 AA)
- Fix Prisma type mismatches (OR filter, Person.companyId, Estimate.projectId, Ticket.createdAt)
- Fix webhook PATCH route (moved to [id]/route.ts)
- Fix mobile-bottom-nav type safety
- Fix KB route where-clause type
- Fix test-mail banner null vs undefined
- Fix task comment fetch: add cancellation + error toast
- ESLint: 0 errors, 0 warnings
- 175 files, 24.741 lines of code

src/components/aos/mobile-bottom-nav.tsx

@@ -0,0 +1,63 @@
+'use client'
+
+import { useAos, type ViewId } from '@/store/aos'
+import { LayoutDashboard, Radar, FolderKanban, Bell, Menu } from 'lucide-react'
+import { cn } from '@/lib/utils'
+import { useFetch } from '@/hooks/use-fetch'
+
+// Mobile bottom navigation bar (PRD §9: "Mobile: usable PWA for time tracking,
+// approvals and quick CRM lookups"). Shows on mobile only (md:hidden).
+// Provides 5 quick-access destinations optimized for touch.
+export function MobileBottomNav() {
+  const { view, setView, setSidebarOpen, setCommandOpen } = useAos()
+  const { data } = useFetch<{ stats: { total: number; urgent: number } }>('/api/aos/notifications')
+
+  const urgent = data?.stats.urgent ?? 0
+  const total = data?.stats.total ?? 0
+
+  const items: { id: string; label: string; icon: typeof LayoutDashboard; badge?: number }[] = [
+    { id: 'dashboard', label: 'Home', icon: LayoutDashboard },
+    { id: 'leads', label: 'Leads', icon: Radar },
+    { id: 'search', label: 'Suche', icon: Menu },
+    { id: 'projects', label: 'Zeit', icon: FolderKanban },
+    { id: 'notifications', label: 'Alerts', icon: Bell, badge: urgent > 0 ? urgent : total > 0 ? total : undefined },
+  ]
+
+  const handleClick = (id: string) => {
+    if (id === 'search') setCommandOpen(true)
+    else if (id === 'notifications') setView('calendar')
+    else if (id === 'menu') setSidebarOpen(true)
+    else setView(id as ViewId)
+  }
+
+  return (
+    <nav className="fixed bottom-0 left-0 right-0 z-40 flex h-16 items-stretch border-t border-border bg-background/95 backdrop-blur-md md:hidden">
+      {items.map((item) => {
+        const Icon = item.icon
+        const active = view === (item.id === 'notifications' ? 'calendar' : (item.id === 'search' || item.id === 'menu') ? ('' as ViewId) : (item.id as ViewId))
+        return (
+          <button
+            key={item.id}
+            onClick={() => handleClick(item.id)}
+            className={cn(
+              'relative flex flex-1 flex-col items-center justify-center gap-0.5 text-[10px] font-medium transition',
+              active ? 'text-foreground' : 'text-muted-foreground'
+            )}
+            aria-label={item.label}
+          >
+            <div className="relative">
+              <Icon className={cn('size-5', active && 'text-foreground')} />
+              {item.badge !== undefined && item.badge > 0 && (
+                <span className="absolute -right-2 -top-1.5 flex size-4 items-center justify-center rounded-full bg-foreground text-[8px] font-bold text-background">
+                  {item.badge > 9 ? '9+' : item.badge}
+                </span>
+              )}
+            </div>
+            <span>{item.label}</span>
+            {active && <span className="absolute bottom-0 left-1/2 h-0.5 w-8 -translate-x-1/2 rounded-full bg-foreground" />}
+          </button>
+        )
+      })}
+    </nav>
+  )
+}