feat(adminsite): session guards and the auth screens

Route-group layouts do the guarding. A customer session on /staff/* is
redirected to its own home rather than shown a refusal -- there is nothing to
tell them about. This is UX only: admin enforces the same boundary with
RequireStaff/RequireCustomer and answers 404 rather than 403 for another
account's data, which is the layer that actually matters.

Signup carries the honeypot the backend expects and reports "check your
email" rather than claiming an account exists, matching a backend that
creates nothing until the link is opened.

Buttons match site/'s .btn--solid and .btn--line, neutral border included.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

adminsite/app/(customer)/layout.tsx

@@ -0,0 +1,25 @@
+"use client";
+
+import Link from "next/link";
+import { RequireKind } from "@/lib/session";
+
+export default function CustomerLayout({ children }: { children: React.ReactNode }) {
+    return (
+        <RequireKind kind="customer">
+            <nav className="border-b border-rule-soft bg-panel-2">
+                <div className="mx-auto flex max-w-rail flex-wrap gap-5 px-5 py-2.5 font-mono text-[0.72rem] uppercase tracking-[0.06em]">
+                    <Link href="/" className="text-accent">
+                        Overview
+                    </Link>
+                    <Link href="/instances/link" className="text-ink-3">
+                        Link an install
+                    </Link>
+                    <Link href="/billing" className="text-ink-3">
+                        Billing
+                    </Link>
+                </div>
+            </nav>
+            <main className="mx-auto max-w-rail px-5 py-8">{children}</main>
+        </RequireKind>
+    );
+}

adminsite/app/(staff)/staff/layout.tsx

@@ -0,0 +1,29 @@
+"use client";
+
+import Link from "next/link";
+import { RequireKind } from "@/lib/session";
+
+const LINKS = [
+    ["/staff", "Operations"],
+    ["/staff/accounts", "Accounts"],
+    ["/staff/licenses", "Licences"],
+    ["/staff/plans", "Plans"],
+    ["/staff/audit", "Audit"],
+] as const;
+
+export default function StaffLayout({ children }: { children: React.ReactNode }) {
+    return (
+        <RequireKind kind="staff">
+            <nav className="border-b border-rule-soft bg-panel-2">
+                <div className="mx-auto flex max-w-rail flex-wrap gap-5 px-5 py-2.5 font-mono text-[0.72rem] uppercase tracking-[0.06em]">
+                    {LINKS.map(([href, label]) => (
+                        <Link key={href} href={href} className="text-ink-3 hover:text-accent">
+                            {label}
+                        </Link>
+                    ))}
+                </div>
+            </nav>
+            <main className="mx-auto max-w-rail px-5 py-8">{children}</main>
+        </RequireKind>
+    );
+}

adminsite/app/login/page.tsx

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+"use client";
+
+import { useRouter } from "next/navigation";
+import { useState } from "react";
+import Link from "next/link";
+import { API_BASE, ApiError, NotConnected, api } from "@/lib/api";
+import { NotConnectedPanel } from "@/components/NotConnected";
+import { Button } from "@/components/Button";
+import { Field } from "@/components/Field";
+
+export default function LoginPage() {
+    const router = useRouter();
+    const [email, setEmail] = useState("");
+    const [password, setPassword] = useState("");
+    const [staff, setStaff] = useState(false);
+    const [error, setError] = useState<string | null>(null);
+    const [offline, setOffline] = useState(false);
+    const [busy, setBusy] = useState(false);
+
+    async function submit(e: React.FormEvent) {
+        e.preventDefault();
+        setBusy(true);
+        setError(null);
+        try {
+            const s = staff
+                ? await api.staffLogin(email, password)
+                : await api.login(email, password);
+            router.replace(s.kind === "staff" ? "/staff" : "/");
+        } catch (err) {
+            if (err instanceof NotConnected) setOffline(true);
+            else if (err instanceof ApiError) setError(err.message);
+            else setError("Sign in failed. Try again.");
+        } finally {
+            setBusy(false);
+        }
+    }
+
+    if (offline)
+        return (
+            <Main>
+                <NotConnectedPanel url={API_BASE} />
+            </Main>
+        );
+
+    return (
+        <Main>
+            <h1 className="text-3xl">Sign in</h1>
+            <form onSubmit={submit} className="mt-6 grid gap-4">
+                <Field
+                    label="Email"
+                    type="email"
+                    autoComplete="username"
+                    required
+                    value={email}
+                    onChange={(e) => setEmail(e.target.value)}
+                />
+                <Field
+                    label="Password"
+                    type="password"
+                    autoComplete="current-password"
+                    required
+                    value={password}
+                    onChange={(e) => setPassword(e.target.value)}
+                    error={error ?? undefined}
+                />
+                <label className="flex items-center gap-2 text-[0.82rem] text-ink-2">
+                    <input
+                        type="checkbox"
+                        checked={staff}
+                        onChange={(e) => setStaff(e.target.checked)}
+                    />
+                    I work at Vantage
+                </label>
+                <div className="flex flex-wrap items-center gap-3">
+                    <Button type="submit" disabled={busy}>
+                        {busy ? "Signing in…" : "Sign in"}
+                    </Button>
+                    <Link href="/signup" className="text-[0.82rem] text-accent underline">
+                        Create an account for a self-hosted licence
+                    </Link>
+                </div>
+            </form>
+        </Main>
+    );
+}
+
+function Main({ children }: { children: React.ReactNode }) {
+    return <main className="mx-auto max-w-rail px-5 py-12">{children}</main>;
+}

adminsite/app/not-found.tsx

@@ -0,0 +1,15 @@
+import Link from "next/link";
+
+export default function NotFound() {
+    return (
+        <main className="mx-auto max-w-rail px-5 py-12">
+            <h1 className="text-3xl">Nothing here</h1>
+            <p className="mt-2 text-ink-2">
+                That page does not exist, or it belongs to an account you are not signed in to.
+            </p>
+            <Link href="/" className="mt-4 inline-block text-accent underline">
+                Back to your account
+            </Link>
+        </main>
+    );
+}

adminsite/app/signup/page.tsx

@@ -0,0 +1,92 @@
+"use client";
+
+import { useState } from "react";
+import { ApiError, NotConnected, api } from "@/lib/api";
+import { Button } from "@/components/Button";
+import { Field } from "@/components/Field";
+
+export default function SignupPage() {
+    const [form, setForm] = useState({ name: "", email: "", password: "", website: "" });
+    const [state, setState] = useState<"idle" | "busy" | "sent">("idle");
+    const [error, setError] = useState<string | null>(null);
+
+    async function submit(e: React.FormEvent) {
+        e.preventDefault();
+        setState("busy");
+        setError(null);
+        try {
+            await api.signup(form);
+            setState("sent");
+        } catch (err) {
+            setState("idle");
+            setError(
+                err instanceof NotConnected
+                    ? "The licensing service is not reachable from this page."
+                    : err instanceof ApiError
+                      ? err.message
+                      : "Could not create the account. Try again.",
+            );
+        }
+    }
+
+    return (
+        <main className="mx-auto max-w-rail px-5 py-12">
+            {state === "sent" ? (
+                <div className="grid max-w-xl gap-3">
+                    <h1 className="text-3xl">Check your email</h1>
+                    <p className="text-ink-2">
+                        We sent a link to {form.email}. Open it to finish setting up your account —
+                        it expires in 24 hours. Nothing is created until you do.
+                    </p>
+                </div>
+            ) : (
+                <>
+                    <h1 className="text-3xl">Create an account</h1>
+                    <p className="mt-2 max-w-xl text-ink-2">
+                        For self-hosted licences. If you run on our cloud, sign in with the same
+                        details you use for your Vantage instance.
+                    </p>
+                    <form onSubmit={submit} className="mt-6 grid gap-4">
+                        <Field
+                            label="Organisation"
+                            required
+                            value={form.name}
+                            onChange={(e) => setForm({ ...form, name: e.target.value })}
+                        />
+                        <Field
+                            label="Email"
+                            type="email"
+                            required
+                            value={form.email}
+                            onChange={(e) => setForm({ ...form, email: e.target.value })}
+                        />
+                        <Field
+                            label="Password"
+                            type="password"
+                            required
+                            minLength={12}
+                            hint="At least 12 characters."
+                            value={form.password}
+                            onChange={(e) => setForm({ ...form, password: e.target.value })}
+                            error={error ?? undefined}
+                        />
+                        {/* Honeypot: off-screen, unlabelled for humans, irresistible to bots. */}
+                        <input
+                            type="text"
+                            name="website"
+                            tabIndex={-1}
+                            autoComplete="off"
+                            aria-hidden="true"
+                            value={form.website}
+                            onChange={(e) => setForm({ ...form, website: e.target.value })}
+                            className="absolute left-[-9999px] h-0 w-0"
+                        />
+                        <Button type="submit" disabled={state === "busy"}>
+                            {state === "busy" ? "Creating…" : "Create account"}
+                        </Button>
+                    </form>
+                </>
+            )}
+        </main>
+    );
+}

adminsite/app/verify/page.tsx

@@ -0,0 +1,62 @@
+"use client";
+
+import { useQuery } from "@tanstack/react-query";
+import { useSearchParams } from "next/navigation";
+import Link from "next/link";
+import { Suspense } from "react";
+import { api } from "@/lib/api";
+
+function Verify() {
+    const token = useSearchParams().get("token") ?? "";
+    const { data, error, isLoading } = useQuery({
+        queryKey: ["verify", token],
+        queryFn: () => api.verify(token),
+        enabled: token !== "",
+        retry: false,
+    });
+
+    if (!token)
+        return (
+            <Message
+                title="That link is incomplete"
+                body="It is missing its token. Use the link in the email exactly as sent."
+            />
+        );
+    if (isLoading) return <Message title="Verifying…" body="One moment." />;
+    if (error || !data?.verified)
+        return (
+            <Message
+                title="That link is invalid or has expired"
+                body="Links last 24 hours and can only be used once. Sign up again to get a fresh one."
+            />
+        );
+
+    return (
+        <div className="grid max-w-xl gap-3">
+            <h1 className="text-3xl">Email verified</h1>
+            <p className="text-ink-2">Your account is ready.</p>
+            <Link href="/login" className="justify-self-start text-accent underline">
+                Sign in
+            </Link>
+        </div>
+    );
+}
+
+function Message({ title, body }: { title: string; body: string }) {
+    return (
+        <div className="grid max-w-xl gap-3">
+            <h1 className="text-3xl">{title}</h1>
+            <p className="text-ink-2">{body}</p>
+        </div>
+    );
+}
+
+export default function VerifyPage() {
+    return (
+        <main className="mx-auto max-w-rail px-5 py-12">
+            <Suspense fallback={null}>
+                <Verify />
+            </Suspense>
+        </main>
+    );
+}