feat: loading state and spinner + delete chunk option

frontend/src/components/Spinner.tsx

@@ -0,0 +1,43 @@
+import React from 'react';
+
+type SpinnerProps = {
+  size?: 'small' | 'medium' | 'large';
+  color?: string;
+};
+
+export default function Spinner({
+  size = 'medium',
+  color = 'grey',
+}: SpinnerProps) {
+  const sizeMap = {
+    small: '20px',
+    medium: '30px',
+    large: '40px',
+  };
+  const spinnerSize = sizeMap[size];
+
+  const spinnerStyle = {
+    width: spinnerSize,
+    height: spinnerSize,
+    aspectRatio: '1',
+    borderRadius: '50%',
+    background: `
+      radial-gradient(farthest-side, ${color} 94%, #0000) top/8px 8px no-repeat,
+      conic-gradient(#0000 30%, ${color})
+    `,
+    WebkitMask:
+      'radial-gradient(farthest-side, #0000 calc(100% - 8px), #000 0)',
+    animation: 'l13 1s infinite linear',
+  } as React.CSSProperties;
+
+  const keyframesStyle = `@keyframes l13 {
+    100% { transform: rotate(1turn) }
+  }`;
+
+  return (
+    <>
+      <style>{keyframesStyle}</style>
+      <div className="loader" style={spinnerStyle} />
+    </>
+  );
+}