feat: implement CookieBridge M1 — core protocol & relay server

- Protocol spec: encrypted envelope format, device identity (Ed25519 + X25519),
  LWW conflict resolution with Lamport clocks
- E2E encryption: XChaCha20-Poly1305 via sodium-native, X25519 key exchange
- WebSocket relay server: stateless message forwarding, device auth via
  challenge-response, offline message queuing, ping/pong keepalive
- Device pairing: time-limited pairing codes, key exchange broker via HTTP
- Sync protocol: envelope builder/opener, conflict-resolving cookie store
- 31 tests passing (crypto, pairing, conflict resolution, full integration)

Co-Authored-By: Paperclip <noreply@paperclip.ing>

package.json

@@ -0,0 +1,33 @@
+{
+  "name": "cookiebridge",
+  "version": "0.1.0",
+  "description": "Cross-device cookie synchronization with E2E encryption",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "scripts": {
+    "build": "tsc",
+    "start": "tsx src/cli.ts",
+    "dev": "tsx --watch src/cli.ts",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "typecheck": "tsc --noEmit"
+  },
+  "keywords": ["cookies", "sync", "encryption", "browser-extension"],
+  "author": "Rc707Agency",
+  "license": "MIT",
+  "type": "commonjs",
+  "dependencies": {
+    "sodium-native": "^5.1.0",
+    "typescript": "^5.9.3",
+    "uuid": "^13.0.0",
+    "ws": "^8.19.0"
+  },
+  "devDependencies": {
+    "@types/node": "^25.5.0",
+    "@types/sodium-native": "^2.3.9",
+    "@types/uuid": "^10.0.0",
+    "@types/ws": "^8.18.1",
+    "tsx": "^4.21.0",
+    "vitest": "^4.1.0"
+  }
+}