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.

docker-compose.yml

@@ -0,0 +1,8 @@
+services:
+    web:
+        image: git.fristy.net/fristy/fristynet:latest
+        restart: unless-stopped
+        environment:
+            TWITCH_CLIENT_ID: ${TWITCH_CLIENT_ID}
+            TWITCH_CLIENT_SECRET: ${TWITCH_CLIENT_SECRET}
+            ITAD_API_KEY: ${ITAD_API_KEY}