Email confirmation, change email/password, show/hide passwords

- Sign-up emails a confirmation link (24h); unconfirmed accounts see a
  banner on the web with "send it again", and status in Settings.
- Change email (needs the password): the new address gets a confirmation
  link and only replaces the old one once clicked; the old address gets a
  heads-up with a reset-password link. Pending changes can be cancelled.
- Change password (needs the current one): signs out other sessions.
- Password fields have Show/Hide on web and mobile.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

apps/web/src/app/settings/page.tsx

@@ -40,6 +40,7 @@ function Settings() {
     <div className="stack">
       <h1>Settings</h1>
       <ProfileForm me={me} />
+      <AccountSettings me={me} />
       <SharingControls />
       <Connections />
       <FeaturedPicker />
@@ -148,6 +149,129 @@ function AvatarPicker({ me }: { me: MeDTO }) {
   );
 }
 
+function AccountSettings({ me }: { me: MeDTO }) {
+  const { mutate } = useMe();
+  const [editing, setEditing] = useState<'email' | 'password' | null>(null);
+  const [message, setMessage] = useState<string | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [show, setShow] = useState(false);
+
+  const run = async (fn: () => Promise<unknown>, done: string) => {
+    setError(null);
+    try {
+      await fn();
+      await mutate();
+      setEditing(null);
+      setMessage(done);
+    } catch (err) {
+      setError((err as Error).message);
+    }
+  };
+  const field = (f: FormData, k: string) => String(f.get(k) ?? '');
+
+  return (
+    <section className="card form">
+      <h2>Account</h2>
+      <div>
+        <div className="muted">Email</div>
+        <div>
+          {me.email}{' '}
+          {me.emailVerified ? <span className="chip-small">Confirmed</span> : <span className="chip-small danger">Not confirmed</span>}
+        </div>
+        {me.pendingEmail && (
+          <p className="muted">
+            Changing to <strong>{me.pendingEmail}</strong>: open the link we sent there.{' '}
+            <button type="button" className="link-button" onClick={() => run(() => client.cancelEmailChange(), 'Email change cancelled.')}>
+              Cancel
+            </button>
+          </p>
+        )}
+        {!me.emailVerified && !me.pendingEmail && (
+          <button type="button" className="link-button" onClick={() => run(() => client.resendVerification(), `Sent a new link to ${me.email}.`)}>
+            Send the confirmation link again
+          </button>
+        )}
+      </div>
+
+      {editing === 'email' ? (
+        <form
+          className="form"
+          onSubmit={(e) => {
+            e.preventDefault();
+            const f = new FormData(e.currentTarget);
+            const email = field(f, 'email');
+            run(() => client.changeEmail({ email, password: field(f, 'password') }), `Check ${email} for a confirmation link.`);
+          }}
+        >
+          <label>
+            New email
+            <input name="email" type="email" required autoComplete="email" />
+          </label>
+          <label>
+            Your password
+            <input name="password" type={show ? 'text' : 'password'} required autoComplete="current-password" />
+          </label>
+          <ShowPassword show={show} setShow={setShow} />
+          <FormButtons label="Send confirmation link" onCancel={() => setEditing(null)} />
+        </form>
+      ) : editing === 'password' ? (
+        <form
+          className="form"
+          onSubmit={(e) => {
+            e.preventDefault();
+            const f = new FormData(e.currentTarget);
+            run(
+              () => client.changePassword({ currentPassword: field(f, 'current'), newPassword: field(f, 'new') }),
+              'Password changed. Your other devices were signed out.',
+            );
+          }}
+        >
+          <label>
+            Current password
+            <input name="current" type={show ? 'text' : 'password'} required autoComplete="current-password" />
+          </label>
+          <label>
+            New password
+            <input name="new" type={show ? 'text' : 'password'} required minLength={8} maxLength={200} autoComplete="new-password" />
+          </label>
+          <ShowPassword show={show} setShow={setShow} />
+          <FormButtons label="Change password" onCancel={() => setEditing(null)} />
+        </form>
+      ) : (
+        <div className="row">
+          <button type="button" className="btn" onClick={() => (setMessage(null), setEditing('email'))}>
+            Change email
+          </button>
+          <button type="button" className="btn" onClick={() => (setMessage(null), setEditing('password'))}>
+            Change password
+          </button>
+        </div>
+      )}
+      {message && <p className="muted">{message}</p>}
+      {error && <p className="error">{error}</p>}
+    </section>
+  );
+}
+
+function ShowPassword({ show, setShow }: { show: boolean; setShow: (v: boolean) => void }) {
+  return (
+    <label className="checkbox">
+      <input type="checkbox" checked={show} onChange={(e) => setShow(e.target.checked)} /> Show passwords
+    </label>
+  );
+}
+
+function FormButtons({ label, onCancel }: { label: string; onCancel: () => void }) {
+  return (
+    <div className="row">
+      <button className="btn btn-primary">{label}</button>
+      <button type="button" className="btn" onClick={onCancel}>
+        Cancel
+      </button>
+    </div>
+  );
+}
+
 function BlockedAccounts() {
   const { data: blocked = [], mutate } = useSWR<UserSummaryDTO[]>('/me/blocks', fetcher);
   return (