spike: minimal N-API libdatachannel binding — WebRTC handshake proven

Phase 0 of GoLive rewrite (drop @dank074/node-datachannel 771MB):
minimal N-API binding exposing PeerConnection/DataChannel/ICE/SDP,
built against libdatachannel 0.24.0 (from node-datachannel _deps source).

Verified: offer/answer/ICE/DataChannel roundtrip between two local
peers (test-handshake.js). Key findings:
- callbacks must be registered in ctor BEFORE createDataChannel
- SDP with candidates comes from localDescription() at gathering Complete
- answer auto-generates on setRemoteDescription(offer); do NOT call
  setLocalDescription() after or role=actpass breaks the peer

services/discord-gateway/native/libdatachannel-min/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "libdatachannel-min",
+  "version": "0.1.0",
+  "description": "Minimal N-API binding to libdatachannel — PeerConnection, DataChannel, ICE, SDP (+ media tracks for GoLive)",
+  "main": "index.js",
+  "gypfile": true,
+  "scripts": {
+    "build": "node-gyp rebuild",
+    "test": "node test-handshake.js"
+  },
+  "dependencies": {
+    "node-addon-api": "^8.3.0"
+  },
+  "devDependencies": {
+    "node-gyp": "^11.5.0"
+  }
+}