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/app/layout.tsx

@@ -0,0 +1,68 @@
+import type { Metadata } from "next";
+import { Geist, Geist_Mono } from "next/font/google";
+import "./globals.css";
+import { Toaster as Sonner } from "@/components/ui/sonner";
+import { ThemeProvider } from "@/components/theme-provider";
+
+const geistSans = Geist({
+  variable: "--font-geist-sans",
+  subsets: ["latin"],
+});
+
+const geistMono = Geist_Mono({
+  variable: "--font-geist-mono",
+  subsets: ["latin"],
+});
+
+export const metadata: Metadata = {
+  title: "AOS — Agency Operating System",
+  description:
+    "Eine selbstgehostete Plattform, die eine Software-Agentur end-to-end betreibt: Leads, CRM, Projekte, Lizenzen, Finanzen — mit EU/DE-Compliance.",
+  keywords: [
+    "AOS",
+    "Agency OS",
+    "CRM",
+    "Leads Finder",
+    "Lizenzmanagement",
+    "E-Rechnung",
+    "DSGVO",
+    "GoBD",
+  ],
+  authors: [{ name: "Nordlicht Digital GmbH" }],
+  manifest: "/manifest.json",
+  appleWebApp: {
+    capable: true,
+    title: "AOS",
+    statusBarStyle: "black",
+  },
+  icons: {
+    icon: "https://z-cdn.chatglm.cn/z-ai/static/logo.svg",
+    apple: "https://z-cdn.chatglm.cn/z-ai/static/logo.svg",
+  },
+  openGraph: {
+    title: "AOS — Agency Operating System",
+    description:
+      "Selbstgehostete Agentur-Plattform mit CRM, Leads Finder, Projekten, Lizenzen und Finanzen.",
+    siteName: "AOS",
+    type: "website",
+  },
+};
+
+export default function RootLayout({
+  children,
+}: Readonly<{
+  children: React.ReactNode;
+}>) {
+  return (
+    <html lang="de" suppressHydrationWarning>
+      <body
+        className={`${geistSans.variable} ${geistMono.variable} antialiased bg-background text-foreground`}
+      >
+        <ThemeProvider attribute="class" defaultTheme="light" enableSystem={false}>
+          {children}
+          <Sonner position="bottom-right" richColors={false} closeButton />
+        </ThemeProvider>
+      </body>
+    </html>
+  );
+}