Dashboard: list the rules' quotas

A Quotas panel with each quota's allowance, use (or, per address, the
count and the busiest), a usage bar and the next reset. The usage bar
moves to widgets.js and the Rules page's usage dialog shares it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/web/static/assets/widgets.js

@@ -156,6 +156,13 @@ export function fmtBytes(n) {
   return n + " bytes";
 }
 
+// usageBar draws used out of total as a bar, red once it is all used.
+export function usageBar(used, total) {
+  const seg = h("div", { class: "seg leased" });
+  seg.style.width = Math.min(100, used / total * 100) + "%";
+  return h("div", { class: "usage" }, h("div", { class: "usage-bar" + (used >= total ? " full" : "") }, seg));
+}
+
 // quotas loads what the rules' quotas used, by rule ID ({} without
 // log:read).
 export async function quotas() {