Add ZXDB breadcrumbs and release places

Add ZXDB breadcrumbs on list/detail pages and group release
magazine references by issue for clearer Places view.

Signed-off-by: codex@lucy.xalior.com

src/app/zxdb/components/ZxdbBreadcrumbs.tsx

@@ -0,0 +1,27 @@
+import Link from "next/link";
+
+type Crumb = {
+  label: string;
+  href?: string;
+};
+
+export default function ZxdbBreadcrumbs({ items }: { items: Crumb[] }) {
+  if (items.length === 0) return null;
+
+  const lastIndex = items.length - 1;
+
+  return (
+    <nav aria-label="breadcrumb">
+      <ol className="breadcrumb">
+        {items.map((item, index) => {
+          const isActive = index === lastIndex || !item.href;
+          return (
+            <li key={`${item.label}-${index}`} className={`breadcrumb-item${isActive ? " active" : ""}`} aria-current={isActive ? "page" : undefined}>
+              {isActive ? item.label : <Link href={item.href ?? "#"}>{item.label}</Link>}
+            </li>
+          );
+        })}
+      </ol>
+    </nav>
+  );
+}