feat: email+password auth with db-backed sessions

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/app/layout.tsx

@@ -1,4 +1,7 @@
-export default function Console({ children }: { children: React.ReactNode }) {
+import { requireUser } from "@/lib/auth";
+
+export default async function Console({ children }: { children: React.ReactNode }) {
+  await requireUser();
   return <div className="shell">
     <aside className="rail" aria-label="Previous analyses">qAI</aside>
     <main className="main">{children}</main>