feat: add TS3 identity generation with Ed25519 keypairs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -12,6 +12,7 @@
         "better-sqlite3": "^12.8.0",
         "express": "^5.2.1",
         "pino": "^10.3.1",
+        "tweetnacl": "^1.0.3",
         "ws": "^8.20.0"
       },
       "devDependencies": {
@@ -3080,6 +3081,12 @@
         "node": "*"
       }
     },
+    "node_modules/tweetnacl": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/tweetnacl/-/tweetnacl-1.0.3.tgz",
+      "integrity": "sha512-6rt+RN7aOi1nGMyC4Xa5DdYiukl2UWCbcJft7YhxReBGQD7OAM8Pbxw6YMo4r2diNEA8FEmu32YOn9rhaiE5yw==",
+      "license": "Unlicense"
+    },
     "node_modules/type-is": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/type-is/-/type-is-2.0.1.tgz",