Undo the test-suite workarounds for the broken manifests

With the manifests broken, b65f265 and 4539abb worked around the symptoms:
rootJs imported itself by relative path instead of as @pezkuwi/dev, a
hand-written dynamic.d.mts stood in for the .mjs, and suite.spec.ts declared
its own describe/it/expect and imported a .d.ts at run time, which failed
the file. All three are reverted to upstream's form.

The import-attribute check now expects `with`: Node 22 removed `assert`.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

packages/dev/src/rootEsm.spec.ts

@@ -3,16 +3,16 @@
 
 import type { Describe, It } from '@pezkuwi/dev-test/env/suite.js';
 
-declare const describe: Describe;
-declare const it: It;
-declare const expect: (value: unknown) => { toBe: (expected: boolean) => void; toEqual: (expected: unknown) => void };
-
 import fs from 'node:fs';
 import path from 'node:path';
 
 import * as testRoot from './root.js';
 import { runTests } from './rootTests.js';
 
+declare const describe: Describe;
+declare const it: It;
+declare const expect: (value: unknown) => { toBe: (expected: boolean) => void; toEqual: (expected: unknown) => void };
+
 runTests(testRoot);
 
 describe('as-built output checks', (): void => {
@@ -91,8 +91,8 @@ describe('as-built output checks', (): void => {
             jsIdx[type].includes(
               type === 'cjs'
                 ? 'require("@pezkuwi/dev/rootJs/testJson.json")'
-                // eslint-disable-next-line no-useless-escape
-                : "import testJson from '@pezkuwi/dev/rootJs/testJson.json' assert { type: \'json\' };"
+                // `with`, not `assert`: Node 22 removed import assertions
+                : "import testJson from '@pezkuwi/dev/rootJs/testJson.json' with { type: 'json' };"
             )
           ).toBe(true);
         })