feat: add PNG/SVG export and expandable card property tips

Toolbar exports PNG (fit+raster) and SVG; card click expands full fields, hover shows property tooltips, double-click opens the editor.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/web/src/PropTooltip.tsx

@@ -0,0 +1,20 @@
+/** Floating property detail tip (card view hover). */
+
+export function PropTooltip({
+  label,
+  value,
+  x,
+  y,
+}: {
+  label: string;
+  value: string;
+  x: number;
+  y: number;
+}) {
+  return (
+    <div className="prop-tooltip" style={{ left: x, top: y }} role="tooltip">
+      <div className="prop-tooltip__label">{label}</div>
+      <div className="prop-tooltip__value">{value}</div>
+    </div>
+  );
+}