Stop a banner rule from being read as a section heading

Three # rules open most docs here, so the title became a section too small to
survive and the paragraph defining the project got a chunk with no heading.

AI/lib/chunk.js

@@ -149,7 +149,22 @@ function sectionsFromMarkdown(text) {
     for (let i = 0; i < lines.length; i++) {
         if (/^\s*```/.test(lines[i])) { fence = !fence; continue; }
         if (fence) continue;
-        if (/^#{1,3}\s+\S/.test(lines[i])) marks.push(i);
+        // A heading whose text is nothing but rule characters is a banner, not a section. The
+        // house style opens a document with three of them —
+        //     # ━━━━━━━━
+        //     # 🏠  VARAVERK
+        //     # ━━━━━━━━
+        // — and treating each as a boundary split the title into a section of its own, too small
+        // to survive, then gave the paragraph that actually defines the project a chunk headed by
+        // the rule beneath it: no heading, and content opening with 75 identical glyphs. That is
+        // why "what is Varaverk" returned five script PURPOSE headers and never README.md, which
+        // has been indexed the whole time. 35 of the 40 markdown files here open this way.
+        //
+        // Whole-string test, so an ordinary heading containing a dash is unaffected — "Set-up"
+        // does not reduce to empty, and a line of dashes does.
+        if (!/^#{1,3}\s+\S/.test(lines[i])) continue;
+        if (lines[i].replace(/^#+\s*/, '').replace(/[━─═=~_*\-\s]+/gu, '') === '') continue;
+        marks.push(i);
     }
     if (!marks.length) return [{ heading: null, content: text.trim() }];