Allow owned loopback Postgres databases in recovery qualification

Co-Authored-By: Paperclip <noreply@paperclip.ing>

tests/runner-e2e/external-controller-database.ts

@@ -0,0 +1,47 @@
+/** Launcher-owned disposable database. The admin credential never enters the
+ * server/browser environment. Unknown remote cleanup keeps this database alive. */
+import { randomUUID } from "node:crypto";
+import { mkdir, readFile, writeFile } from "node:fs/promises";
+import { createDb } from "../../packages/db/src/index.js";
+import { paperclipConfigSchema } from "../../packages/shared/src/config-schema.js";
+import { recordControllerDatabaseOwnership } from "./instance-isolation.js";
+import { prepareRunnerE2EServerConfig } from "./server-config.js";
+
+export async function createExternalControllerDatabase(input: {
+  adminUrl: string; temporaryRoot: string; configPath: string; serverPort: number;
+}) {
+  const url = new URL(input.adminUrl);
+  if (!["postgres:", "postgresql:"].includes(url.protocol)
+    || !["127.0.0.1", "localhost", "[::1]"].includes(url.hostname)) {
+    throw new Error("E2E Postgres administrator must use an explicit loopback test server");
+  }
+  await (await prepareRunnerE2EServerConfig(input))?.close();
+  const config = paperclipConfigSchema.parse(JSON.parse(await readFile(input.configPath, "utf8")));
+  if (config.database.mode !== "embedded-postgres") throw new Error("E2E database fixture already configured");
+  const databaseName = `runner_e2e_${randomUUID().replaceAll("-", "")}`;
+  const admin = createDb(input.adminUrl, { maxConnections: 1 });
+  let created = false;
+  const cleanup = async () => {
+    if (!created) return;
+    const connection = createDb(input.adminUrl, { maxConnections: 1 });
+    try {
+      // No FORCE: a remaining controller keeps its evidence and fails cleanup.
+      await connection.$client.unsafe(`drop database "${databaseName}"`);
+      created = false;
+    } finally { await connection.$client.end({ timeout: 1 }); }
+  };
+  try {
+    await admin.$client.unsafe(`create database "${databaseName}"`);
+    created = true;
+    url.pathname = `/${databaseName}`;
+    config.database = { ...config.database, mode: "postgres", connectionString: url.toString() };
+    await mkdir(config.database.embeddedPostgresDataDir, { recursive: true, mode: 0o700 });
+    await recordControllerDatabaseOwnership({ ...input, dataDirectory: config.database.embeddedPostgresDataDir,
+      connectionString: url.toString(), externalDatabaseName: databaseName });
+    await writeFile(input.configPath, `${JSON.stringify(config, null, 2)}\n`, { mode: 0o600 });
+    return { cleanup };
+  } catch (error) {
+    await cleanup();
+    throw error;
+  } finally { await admin.$client.end({ timeout: 1 }); }
+}