fix(docker): replace better-sqlite3 with pure-JS JSON token store

better-sqlite3 is a native C++ addon that requires compilation on Alpine
(musl libc, no pre-built binaries exist) and fails on Debian slim too
because prebuild-install cannot detect the libc type correctly.

Replace with a pure-JS JSON file token store (server/utils/tokenStore.js):
- Atomic writes via temp file + rename (no corruption on crash)
- Same API: storeToken/getToken/clearToken
- TTL enforcement on read and hourly prune
- Zero native code, zero build tools required

Dockerfile:
- Revert to node:22-alpine (was node:22-slim)
- Remove build tools (python3/make/g++) — no longer needed
- Restore wget HEALTHCHECK (available in Alpine busybox)

docker-compose.yaml: restore wget healthcheck

package.json: remove better-sqlite3 dependency

package.json

@@ -13,9 +13,7 @@
   },
   "dependencies": {
     "axios": "^1.6.0",
-    "better-sqlite3": "^9.0.0",
     "cookie-parser": "^1.4.6",
-    "dotenv": "^16.3.1",
     "express": "^4.18.2",
     "express-rate-limit": "^7.0.0",
     "helmet": "^7.0.0"