feat: deliver module database ABI by manifest

apps/api/tests/module-database.integration.ts

@@ -8,6 +8,7 @@ import {
   createPostgresMigrationDatabase,
   discoverAllMigrations,
 } from "@ekklesia/core/migrations";
+import { moduleDatabaseExecutorModuleId } from "@ekklesia/core/modules";
 import { Client, type QueryResultRow } from "pg";
 import { afterAll, describe, expect, it } from "vitest";
 import { createApiRuntimeConfig } from "../src/config.js";
@@ -441,6 +442,11 @@ describe.sequential("live API — module database explicit migration ownership",
 
       const handle = createApiDatabase(database.url);
       expect(handle.module).toBeDefined();
+      const alpha = handle.moduleExecutor("alpha");
+      const beta = handle.moduleExecutor("beta");
+      expect(alpha).not.toBe(beta);
+      expect(moduleDatabaseExecutorModuleId(alpha)).toBe("alpha");
+      expect(moduleDatabaseExecutorModuleId(beta)).toBe("beta");
       await handle.close();
       expect(await tableExists(database.url)).toBe(false);