Web UI: links to a rule open it, highlighted; rule IDs shown

A rule named in the matrix, the log, the tracer, statistics or the
dashboard opens the Rules page on its chain, scrolled to it and
highlighted (#/rules?rule=ID; the chain is looked up when the link has
none). The Rules page shows each rule's ID beside its order.

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

internal/web/static/assets/pages/stats.js

@@ -180,7 +180,7 @@ function rangeRow(since) {
 // ruleHref: a counter's mark to its page ("r12" → the rules, "b-…" → the
 // built-ins under Settings).
 function ruleHref(mark) {
-  if (/^r\d/.test(mark)) return "#/rules";
+  if (/^r\d+$/.test(mark)) return "#/rules?rule=" + mark.slice(1);
   if (mark.startsWith("b-") || mark.startsWith("p-")) return "#/settings";
   if (mark.startsWith("f")) return "#/nat";
   return null;