perf: pre-compress gamedata JSON, tune MariaDB, fix avatar imager, docs

- scripts/compress-gamedata.mjs: pre-compress large gamedata JSON to .gz
  (gzip level 9, idempotent mtime check) served via nginx gzip_static
  (48 MB FurnitureData.json -> ~2.4 MB, ~0.3s -> ~0.005s per request)
- package.json: add gamedata:compress script
- fix(imaging): accept real Habbo figure strings in avatar route
  (allow optional second number per part, e.g. hd-180-1.ch-210-66)
- README: document avatar imager container (avatar-imaging-pixinode,
  port 8082, /docker/Polaris-imager), nginx /imaging proxying, MariaDB
  tuning, gamedata pre-compression cron and caching layers

src/app/api/imaging/avatar/route.ts

@@ -1,7 +1,7 @@
 import { type NextRequest, NextResponse } from "next/server";
 import { resolveImagerBase } from "@/lib/imager";
 
-const FIGURE_RE = /^([a-z]{2}-\d+)(\.[a-z]{2}-\d+)*$/i;
+const FIGURE_RE = /^[a-z]{2}-\d+(-\d+)?(\.[a-z]{2}-\d+(-\d+)?)*$/i;
 const FIGURE_MAX_LEN = 512;
 const FIGURE_MAX_PARTS = 24;
 const UPSTREAM_TIMEOUT_MS = 10_000;