v1.9.0: Full diagnostic sweep - 42 issues fixed

Critical fixes (7):
- Added global Express error handler (returns JSON instead of HTML)
- Removed caching from random endpoint (defeated purpose)
- Renamed share.jpg to share.png (MIME type mismatch)
- Fixed OG image dimensions (630 → 601)
- Fixed manifest.json icon sizes (192x192 → 512x512)
- Fixed implicit global event variable in console
- Added 9 missing endpoints to docs/endpoints.md

High fixes (12):
- Imported version from package.json (no hardcoded drift)
- Added dynamic endpoint count in stats
- Added input sanitization for mapper API (SSRF prevention)
- Added homepage caching (reduced 5 duplicate HTTP requests)
- Added rate limiting (100 requests/minute per IP)
- Added rel="noopener noreferrer" to all target="_blank" links
- Fixed trailing slash inconsistency in console
- Added noindex meta to 404.html
- Fixed docs/architecture.md controller filenames and dependency versions
- Fixed README.md dependency versions
- Added 12 missing endpoint tests

Medium fixes (22):
- Added escapeHtml helper for error messages
- Consistent favicon across all pages
- Added meta descriptions to privacy.html and tos.html
- Added OG/Twitter meta tags to privacy.html and tos.html
- Added aria-label to playground inputs
- Added aria-hidden to decorative SVGs
- Synced Twitter description with OG description
- Fixed robots.txt to disallow /api
- Added PWA fields to manifest.json
- Removed 5 unused imports
- Removed unused cookie-parser dependency
- Fixed inconsistent error handling in extractors
- Fixed resolvedSlug returning numeric ID
- Added /watch endpoint to streaming docs
- Improved test assertions and status code validation
- Deleted orphaned og-image.svg and logo.png

Low fixes (11):
- Removed redundant try/catch from extractPages
- Added max size eviction to cache
- Added cache key sorting in filter controller
- Added author meta tag
- Fixed favicon.svg font

Version bumped to 1.9.0

src/extractors/episodeList.extractor.js

@@ -56,7 +56,7 @@ const extractEpisodeList = async (slugOrId) => {
     }
 
     if (!animeId) {
-      return { animeId: 0, slug: resolvedSlug, totalEpisodes: 0, episodes: [] };
+      return { animeId: 0, slug: slugOrId, totalEpisodes: 0, episodes: [] };
     }
 
     try {
@@ -104,7 +104,7 @@ const extractEpisodeList = async (slugOrId) => {
 
       return {
         animeId,
-        slug: resolvedSlug,
+        slug: slugOrId,
         totalEpisodes: episodes.length,
         episodes
       };
@@ -112,7 +112,7 @@ const extractEpisodeList = async (slugOrId) => {
       // NOTE: Gracefully return empty list if AJAX call fails (e.g. network issue)
       return {
         animeId,
-        slug: resolvedSlug,
+        slug: slugOrId,
         totalEpisodes: 0,
         episodes: []
       };