test(dogfood): the newly landed position-environment-write-through boot goes through bootShowcase

bootShowcase passes the showcase's own directory as hostRoot, so the file no
longer changes the process cwd to reach it. Its databaseFile option and its two
reboots after stop() are unchanged.

Claude-Session: https://claude.ai/code/session_01DhTqaEHqPVSVnAkjG3jywn
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/qa/dogfood/test/position-environment-write-through.dogfood.test.ts

@@ -31,22 +31,18 @@
 //    boot changes nothing.
 
 import { describe, it, expect, beforeAll, afterAll } from 'vitest';
-import showcaseStack from '@objectstack/example-showcase';
-import { bootStack, type VerifyStack } from '@objectstack/verify';
+import { type VerifyStack } from '@objectstack/verify';
+import { bootShowcase } from './showcase-boot.js';
 import { createSecurityCatalogReader } from '@objectstack/core';
-import { fileURLToPath } from 'node:url';
 import { mkdtempSync, rmSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 
-/** Package-relative refs resolve against the cwd — see the sibling cold-boot files. */
-const SHOWCASE_DIR = fileURLToPath(new URL('../../../../examples/app-showcase/', import.meta.url));
 const SYS = { context: { isSystem: true } } as const;
 /** The backfill's ledger row (`position-environment-backfill.ts`). */
 const LEDGER_ID = 'adr-0131-position-environment-backfill';
 
 describe('[ADR-0131 D3] Setup positions reach the environment ledger under single (showcase)', () => {
-  let prevCwd: string;
   let dir: string;
   let db: string;
   let stack: VerifyStack | undefined;
@@ -68,22 +64,19 @@ describe('[ADR-0131 D3] Setup positions reach the environment ledger under singl
     return entry !== undefined && entry.name === name;
   };
   const start = async () => {
-    stack = await bootStack(showcaseStack, { databaseFile: db });
+    stack = await bootShowcase({ databaseFile: db });
     token = await stack.signIn();
     ql = await stack.kernel.getServiceAsync('objectql');
   };
 
   beforeAll(async () => {
-    prevCwd = process.cwd();
-    process.chdir(SHOWCASE_DIR);
     dir = mkdtempSync(join(tmpdir(), 'dogfood-15196-s7-'));
     db = join(dir, 'showcase.db');
     await start();
   }, 300_000);
 
   afterAll(async () => {
     await stack?.stop();
-    if (prevCwd) process.chdir(prevCwd);
     if (dir) rmSync(dir, { recursive: true, force: true });
   });