fix(test): stream large report snapshot SQL

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

frontend/tests/database-postgres-fixture-contract.test.ts

@@ -0,0 +1,27 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { startPostgresFixture } from "./helpers/postgres-fixture.ts";
+
+test("stdin PostgreSQL scripts carry large SQL and preserve transaction-local settings", () => {
+  const fixture = startPostgresFixture();
+  try {
+    const payload = "x".repeat(131_073);
+    const script = `
+      select set_config('app.test_large_script', 'stdin-helper', true);
+      select current_setting('app.test_large_script');
+      select length($$${payload}$$);
+    `;
+    assert.equal(Buffer.byteLength(script, "utf8") > 131_072, true);
+    assert.equal(
+      fixture.psqlScriptAs("postgres", "postgres-test-password", script),
+      "stdin-helper\nstdin-helper\n131073",
+    );
+    assert.equal(
+      fixture.psqlScriptAs("postgres", "postgres-test-password", "select repeat('x', 1048577);"),
+      "x".repeat(1_048_577),
+    );
+  } finally {
+    fixture.stop();
+  }
+});