fix: resolve HTML hierarchy, accessibility and PDF link issues

- Fix heading level skip in ContactContent success state (H3 -> H2)
- Clean up deprecated iframe attributes in ContactContent
- Add aria-label to footer logo link for WCAG compliance
- Rename PDF assets to hyphenated filenames to fix link checks
- Update AGB page with new PDF link format

scripts/find-empty-anchors.ts

@@ -0,0 +1,14 @@
+import * as cheerio from "cheerio";
+import * as fs from "fs";
+
+const file = process.argv[2];
+const html = fs.readFileSync(file, "utf8");
+const $ = cheerio.load(html);
+
+$("a").each((i, el) => {
+  const text = $(el).text().trim();
+  const label = $(el).attr("aria-label");
+  if (!text && !label) {
+    console.log(`Empty anchor found: ${$(el).toString()}`);
+  }
+});