fix: Full diagnostic sweep — bugs, dead code, unused imports, docs accuracy

Code fixes:
- seasons/watchOrder: Remove dead ternary (both branches identical)
- mirror.helper: Remove redundant ternary (both branches identical)
- topAnimeRankings: Fix JSDoc (day/week/month, not top/newest)
- apiRoutes: Fix proxy domain validation (exact match, not includes)
- apiRoutes: Fix proxy .m3u8 check (pathname, not hostname)
- pagination: Fix totalItems calculation (was overestimating)
- server.js: Remove dead has404File variable
- server.js: Remove duplicate /api/cache/stats route
- server.js: Remove unused getCacheStats import

Unused imports removed:
- animeInfo: URLS from dataUrl.js
- episodeList: headers from header.config.js
- episodeListAjax: axios
- trending: URLS from dataUrl.js
- trendingSidebar: URLS from dataUrl.js
- upcomingAnime: parseListItems
- watchPage: URLS, BASE_URL from dataUrl.js

Docs fixes:
- README: 33->38 endpoints, 24->28 controllers, 26->28 extractors
- README: Cache TTL 5min->per-endpoint, Timeout 15s->30s
- docs/index.md: 33->38 endpoints
- architecture.md: LRU cache strategy, remove stale cookie-parser
- agents: compression version, extractor/controller counts
- agents: domain typo, stale CORS dep, version badge

src/helper/mirror.helper.js

@@ -201,7 +201,7 @@ async function fetchWithMirror(path, options = {}) {
             console.log(`[MIRROR] Switched to: ${mirror}`);
           }
           return { 
-            data: returnType === "text" ? response.data : response.data,
+            data: response.data,
             mirror 
           };
         }