Remove custom Mermaid viewBox fix and switch to unpkg for assets

Switch Mermaid CDN to unpkg and add footer with ICP info

layouts/_partials/custom/head-end.html

@@ -9,56 +9,3 @@
             });
     });
 </script>
-
-<!-- Mermaid config + viewBox from all g elements -->
-<script>
-    (function () {
-        function patch() {
-            if (typeof mermaid === "undefined") return setTimeout(patch, 50);
-            var orig = mermaid.initialize;
-            mermaid.initialize = function (cfg) {
-                cfg = cfg || {};
-                cfg.flowchart = cfg.flowchart || {};
-                cfg.flowchart.useMaxWidth = true;
-                cfg.flowchart.wrappingWidth = 180;
-                cfg.theme = "base";
-                cfg.themeVariables = cfg.themeVariables || {};
-                return orig.call(this, cfg);
-            };
-        }
-        patch();
-
-        function fixViewBox() {
-            document.querySelectorAll(".mermaid svg").forEach(function (svg) {
-                if (svg.getAttribute("aria-roledescription") === "pie") return;
-                var groups = svg.querySelectorAll("g");
-                if (!groups.length) return;
-                var minX = Infinity,
-                    minY = Infinity,
-                    maxX = -Infinity,
-                    maxY = -Infinity;
-                groups.forEach(function (g) {
-                    var bb = g.getBBox();
-                    if (bb.width === 0 || bb.height === 0) return;
-                    if (bb.x < minX) minX = bb.x;
-                    if (bb.y < minY) minY = bb.y;
-                    if (bb.x + bb.width > maxX) maxX = bb.x + bb.width;
-                    if (bb.y + bb.height > maxY) maxY = bb.y + bb.height;
-                });
-                if (!isFinite(minX)) return setTimeout(fixViewBox, 200);
-                var pad = 16;
-                svg.setAttribute(
-                    "viewBox",
-                    [
-                        minX - pad,
-                        minY - pad,
-                        maxX - minX + pad * 2,
-                        maxY - minY + pad * 2,
-                    ].join(" "),
-                );
-            });
-        }
-        setTimeout(fixViewBox, 600);
-        setTimeout(fixViewBox, 1200);
-    })();
-</script>