Make detectMaxPage thread-scoped to avoid sidebar false positives

The previous fallback scanned for any anchor whose text was a number, which
matched widget elements (online count, trending threads, etc.) and inflated
the page count — a sidebar showing "26" caused detectMaxPage to report 26
pages on threads that were actually 12 and 8 pages long.

Now we derive the thread's URL prefix from the input baseUrl and only count
page-N references in hrefs that match that thread, ignoring sidebar
references to unrelated threads. The bare numeric-anchor scan is dropped.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/scrapers/forum.js

@@ -89,29 +89,34 @@ export async function detectMaxPage(baseUrl, logFn, cookies, userAgent, fsSessio
     }
     const $ = cheerio.load(html);
 
+    // Derive the thread's URL prefix so we only count pagination that belongs
+    // to THIS thread. XenForo sidebars/widgets contain page-N references for
+    // unrelated threads, and there are also bare numeric anchors (online count,
+    // trending widgets) that look like page numbers but aren't.
+    let threadPrefix = '';
+    try {
+      const u = new URL(baseUrl);
+      const m = u.pathname.match(/^(\/threads\/[^\/]+)/);
+      if (m) threadPrefix = m[1];
+    } catch {}
+
     let maxPage = 1;
-    $('a.pageNav-page, .pageNav a[href*="page-"], .pagination a[href*="page-"]').each((_, el) => {
+    if (threadPrefix) {
-      const href = $(el).attr('href') || '';
+      const escaped = threadPrefix.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
-      const m = href.match(/page-(\d+)/);
+      const ownRe = new RegExp(escaped + '/page-(\\d+)', 'g');
-      if (m) maxPage = Math.max(maxPage, parseInt(m[1], 10));
-    });
-    $('a').each((_, el) => {
-      const text = $(el).text().trim();
-      if (/^\d+$/.test(text)) {
-        const n = parseInt(text, 10);
-        if (n > maxPage && n < 10000) maxPage = n;
-      }
-    });
-    // Final fallback: scan raw HTML for any page-N references (XenForo's
-    // serialized pagination sometimes only appears in href attributes that
-    // cheerio's class-based selectors miss).
-    if (maxPage === 1) {
-      const re = /page-(\d+)/g;
       let m;
-      while ((m = re.exec(html)) !== null) {
+      while ((m = ownRe.exec(html)) !== null) {
         const n = parseInt(m[1], 10);
         if (n > maxPage && n < 10000) maxPage = n;
       }
+    } else {
+      // No thread prefix (caller passed a non-thread URL) — fall back to the
+      // narrow class-based selectors only, NOT the bare numeric-anchor scan.
+      $('a.pageNav-page, .pageNav a[href*="page-"], .pagination a[href*="page-"]').each((_, el) => {
+        const href = $(el).attr('href') || '';
+        const m = href.match(/page-(\d+)/);
+        if (m) maxPage = Math.max(maxPage, parseInt(m[1], 10));
+      });
     }
 
     if (maxPage > 1) {