feat(desktop): shared PinInput component

apps/desktop/src/components/PinInput.tsx

@@ -0,0 +1,48 @@
+import { useEffect, useRef } from 'react';
+
+interface Props {
+  value: string;
+  onChange: (next: string) => void;
+  length?: number;
+  autoFocus?: boolean;
+  disabled?: boolean;
+  ariaLabel: string;
+  onSubmit?: () => void;
+}
+
+export function PinInput({ value, onChange, length = 6, autoFocus, disabled, ariaLabel, onSubmit }: Props) {
+  const ref = useRef<HTMLInputElement | null>(null);
+  useEffect(() => { if (autoFocus) ref.current?.focus(); }, [autoFocus]);
+  return (
+    <div className="relative flex justify-center" onClick={() => ref.current?.focus()}>
+      <input
+        ref={ref}
+        aria-label={ariaLabel}
+        inputMode="numeric"
+        autoComplete="one-time-code"
+        pattern="\d*"
+        maxLength={length}
+        disabled={disabled}
+        value={value}
+        onChange={(e) => onChange(e.target.value.replace(/\D/g, '').slice(0, length))}
+        onKeyDown={(e) => { if (e.key === 'Enter' && value.length === length) onSubmit?.(); }}
+        className="absolute h-px w-px overflow-hidden p-0 opacity-0"
+      />
+      <div className="flex gap-2">
+        {Array.from({ length }).map((_, i) => {
+          const filled = i < value.length;
+          return (
+            <span key={i}
+              className={
+                'flex h-12 w-10 items-center justify-center rounded-lg border text-lg font-semibold ' +
+                (filled
+                  ? 'border-brand-400 bg-brand-500/10 text-white'
+                  : 'border-white/10 bg-ink-800 text-neutral-500')
+              }
+            >{filled ? '•' : ''}</span>
+          );
+        })}
+      </div>
+    </div>
+  );
+}