desloppify: code health overhaul plus abuse hardening (140 green, strict 87.2)

Honest baseline after removing 45 gaming suppressions. Structural: lib/game plus root hooks extraction, CORS origin echo, DEV_ORIGINS layering. Fixes: error-cause binding, discord 5xx split, null-cache guard, co-located tests, rejecting-fetch coverage, naming and typing cleanup, socket controller, cache bound, cascade helpers, latch resets. Hardening: per-IP rate limit on API routes, deterministic-miss UX, retry cooldown plus cap. Suite 140 green, build plus lint clean.

lib/i18n/dictionaries/en.json

@@ -49,11 +49,12 @@
             "loadError": "Couldn't load game info.",
             "retry": "Retry",
             "partialFail": "Some data failed to load.",
+            "noGameData": "No game data found for this app.",
             "screenshots": "Screenshots",
             "reviewsUnit": "reviews",
             "scrollBack": "Back",
             "scrollForward": "Forward",
-            "totalReviews": "Total Reviews",
+            "totalReviews": "Steam",
             "steamdbRating": "SteamDB Rating",
             "reviewScores": {
                 "overwhelminglyPositive": "Overwhelmingly Positive",