Initial ChronoSeal release

frontend/entropy.js

@@ -0,0 +1,10 @@
+const events = [];
+
+document.addEventListener('mousemove', (e) => {
+    events.push({ x: e.clientX, y: e.clientY, t: performance.now() });
+    if (events.length > 300) events.shift();
+});
+
+export function collectEntropy(since) {
+    return events.filter(e => e.t > since);
+}