Audible: HTML refresh, multi-narrator & works dedup

Switch nightly discovery refresh to scrape Audible's curated HTML storefronts (popular, new releases, category pages) while keeping real-time user paths on the JSON catalog API. Add robust HTML resilience knobs (increased retries, capped jittered backoff, AdaptivePacer changes and per-batch cooldowns) to avoid failing nightly jobs during 503 storms. Implement multi-narrator capture via a new extractAllNarrators helper and update parsers to preserve all narrator anchors. Introduce two-pass dedup: in-memory deduplicateAndCollectGroups + collapseByExistingWorks that consults the works table, export metadataScore for consistent representative selection, and persist dedup groups (fire-and-forget). Wire collapseByExistingWorks into search/author/series routes and make defensive dedup in the refresh processor. Add HTML parsing helpers, runtime/lang-aware parsing, jitteredBackoff cap, and tests for the new behaviors.

src/lib/utils/extract-narrator.ts

@@ -0,0 +1,37 @@
+/**
+ * Component: Narrator Extraction Utility
+ * Documentation: documentation/integrations/audible.md
+ *
+ * Shared helper for Audible HTML scrapers. Audible product listings render
+ * each narrator as a separate `<a href="?searchNarrator=...">` link; using
+ * `.first()` on that selector silently drops co-narrators and breaks dedup
+ * for multi-narrator productions (e.g. full-cast audiobooks). This helper
+ * captures every narrator link and joins them, falling back to the
+ * `.narratorLabel` span when no anchor links are present.
+ */
+
+import type * as cheerio from 'cheerio';
+import type { AnyNode } from 'domhandler';
+
+/**
+ * Extract a comma-joined narrator string from an Audible product list item.
+ *
+ * Order is not semantically significant — downstream `normalizeNarrator()`
+ * sorts before comparison — but document-order preserves a stable, legible
+ * value for caching and logging.
+ */
+export function extractAllNarrators(
+  $: cheerio.CheerioAPI,
+  $el: cheerio.Cheerio<AnyNode>,
+): string {
+  const links = $el.find('a[href*="searchNarrator="]');
+  if (links.length > 0) {
+    const names: string[] = [];
+    links.each((_, link) => {
+      const name = $(link).text().trim();
+      if (name) names.push(name);
+    });
+    if (names.length > 0) return names.join(', ');
+  }
+  return $el.find('.narratorLabel').text().trim();
+}