postgres: the store's query runs as a read-only login, never as the admin (hq #193)

The verb wrapped the caller's text in BEGIN READ ONLY ... ROLLBACK as the superuser, so
'COMMIT; ...' left the transaction and, proven on a throwaway server, COPY TO PROGRAM ran a
shell command on the database host. The statement now runs as mesh_store_reader:
pg_read_all_data, no other grant, read-only transactions by role and session, its password
an own-secret the mesh mints. Without that password the call is refused. -q drops the
command tags that came back as rows keyed by BEGIN.

modules/postgres/package.json

@@ -1,9 +1,13 @@
 {
   "name": "@novox/module-postgres",
   "version": "0.1.0",
-  "description": "postgres — provides the mesh postgres-database interface. Its client, provisioner, tools and events live here (novox/hq ADR 0039).",
+  "description": "postgres \u2014 provides the mesh postgres-database interface. Its client, provisioner, tools and events live here (novox/hq ADR 0039).",
   "type": "module",
   "private": true,
+  "scripts": {
+    "build": "tsc client.ts index.ts provisioner/index.ts tools/index.ts --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist",
+    "test": "npm run build && node --test --experimental-strip-types 'test/*.test.ts'"
+  },
   "dependencies": {
     "@novox/mesh-sdk": "^0.1.1"
   },