fix(infra): build native voice deps (opus, datachannel) in Nix closure

pnpm 11 rebuild hanya jalanin script package yang di-approve via
pnpm-workspace.yaml (allowBuilds) DAN abort di kegagalan pertama.
Yaml harus tracked (flake source cuma ikut file git). Tapi pnpm rebuild
tetap gagal karena: (1) node-crc MSRV cargo:: error — dead dep, dihapus
dari deps+patch; (2) sharp install script gagal di sandbox — binary-nya
prebuilt @img, script cuma validasi — dikeluarkan dari approval list;
(3) node-datachannel prebuild CLI TypeError + cmake-js butuh cwd benar.

Fix: loop eksplisit di buildPhase gateway yang jalankan install script
tiap native dep (opus/node-datachannel/zeromq) dengan cwd package dir,
+ cmake (dontUseCmakeConfigure biar stdenv nggak auto-configure),
+ opensslDevEnv = symlinkJoin pkgsStatic.openssl.out (libcrypto.a —
CMakeLists set OPENSSL_USE_STATIC_LIBS=TRUE; pkgs.openssl default
output = bin tanpa lib) + openssl.dev (headers),
+ git (libdatachannel FetchContent clone dari GitHub).

Verifikasi: result store punya opus.node (compile source), node_datachannel.node
(compile source), node-av prebuilt, zeromq prebuilt; runtime smoke test:
PeerConnection instantiate+close OK, OpusEncoder encode OK, dank074
Streamer/prepareStream/playStream load OK.

services/discord-gateway/package.json

@@ -10,13 +10,9 @@
       "@lng2004/node-datachannel",
       "esbuild",
       "node-av",
-      "node-crc",
       "sharp",
       "zeromq"
-    ],
-    "patchedDependencies": {
-      "node-crc@4.0.0": "./patches/node-crc@4.0.0.patch"
-    }
+    ]
   },
   "scripts": {
     "dev": "tsx watch src/index.ts",
@@ -40,7 +36,6 @@
     "ioredis": "^5.11.0",
     "libsodium-wrappers": "^0.8.4",
     "lru-cache": "^11.5.1",
-    "node-crc": "^4.0.0",
     "openai": "^6.38.0",
     "opusscript": "^0.0.8",
     "p-limit": "^7.3.0",