feat: add direct PostgreSQL and ACK deployment support

tests/postgres-script-contract.test.ts

@@ -0,0 +1,14 @@
+import { readFile } from "node:fs/promises";
+import { describe, expect, it } from "vitest";
+
+describe("PostgreSQL account script concurrency contract", () => {
+  it("serializes bootstrap and legacy imports that target the same logical account", async () => {
+    const [bootstrap, legacyImport] = await Promise.all([
+      readFile(new URL("../scripts/bootstrap-admin.mjs", import.meta.url), "utf8"),
+      readFile(new URL("../scripts/import-legacy-accounts.mjs", import.meta.url), "utf8")
+    ]);
+    expect(bootstrap).toContain("pg_advisory_xact_lock");
+    expect(legacyImport).toContain("pg_advisory_xact_lock(hashtextextended($1, 0))");
+    expect(legacyImport).toContain("session_version=platform_users.session_version+1");
+  });
+});