Initial commit: local network content cache for BgUpd component downloads

Node.js daemon: Ed25519 identity + self-signed TLS, signed registration/
renewal with the central registry, mDNS advertising, disk-backed
fetch-through asset cache with an origin allowlist. Includes a local
dev-registry stand-in for the real oxmc.me endpoints and an end-to-end
smoke test (register -> token -> cache miss/hit -> SSRF rejection).

See README.md for the full protocol and trust model.

package.json

@@ -0,0 +1,22 @@
+{
+  "name": "pawletcache-server",
+  "version": "1.0.0",
+  "description": "Local network content cache for PawletOS device updates (BgUpd component assets).",
+  "license": "Apache-2.0",
+  "type": "commonjs",
+  "main": "src/index.js",
+  "bin": {
+    "pawletcache-server": "src/index.js"
+  },
+  "scripts": {
+    "start": "node src/index.js"
+  },
+  "engines": {
+    "node": ">=20"
+  },
+  "dependencies": {
+    "bonjour-service": "^1.2.1",
+    "js-yaml": "^4.1.0",
+    "selfsigned": "^2.4.1"
+  }
+}