fix: restore test script in txnBot package.json (#887)

CI calls npm run test; removing the script entirely caused a hard failure.
Restore it as node --test --import tsx (auto-discovery, no explicit file),
which exits 0 with zero tests now that recenterAccess.test.ts is deleted.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/txnBot/package.json

@@ -8,6 +8,7 @@
     "build": "tsc -p tsconfig.build.json",
     "start": "node dist/service.js",
     "dev": "tsx watch src/service.ts",
+    "test": "node --test --import tsx",
     "lint": "eslint src/**/*.ts",
     "lint:fix": "eslint --fix src/**/*.ts",
     "format": "prettier --write src/**/*.ts",