chore: establish YCode replication baseline and TODO

scripts/rea/css-runtime-integrity.mjs

@@ -0,0 +1,17 @@
+import assert from 'node:assert/strict'
+import fs from 'node:fs/promises'
+import path from 'node:path'
+import crypto from 'node:crypto'
+
+const runtime = path.resolve('.tmp/rea-css-runtime')
+const manifest = JSON.parse(await fs.readFile(path.join(runtime, 'css-repair-manifest.json'), 'utf8'))
+const sha = bytes => crypto.createHash('sha256').update(bytes).digest('hex')
+for (const file of manifest.files) {
+  assert.equal(sha(await fs.readFile(path.join(runtime, file.path))), file.modified_sha256, `Local repaired module changed: ${file.path}`)
+  if (file.original_sha256 !== null) {
+    assert.equal(sha(await fs.readFile(path.join(manifest.sourceRoot, file.path))), file.original_sha256, `Global REA module changed: ${file.path}`)
+    assert.equal(sha(await fs.readFile(path.join(runtime, 'css-repair-baseline', file.path))), file.original_sha256)
+  }
+}
+assert.equal(await fs.realpath(path.join(runtime, 'node_modules')), await fs.realpath(path.join(manifest.sourceRoot, 'node_modules')))
+console.log(`REA local repair integrity passed: ${manifest.files.length} module digests; corresponding global files unchanged`)