test(M01-B): 验证MySQL迁移往返

scripts/dev/windows/check-backend.ps1

@@ -17,7 +17,9 @@ $requiredFiles = @(
   "backend/tests/migration-contract.test.mjs",
   "backend/tests/mysql-pool-contract.test.mjs",
   "backend/tests/migration-runner.test.mjs",
+  "backend/tests/mysql-migration-roundtrip.test.mjs",
   "backend/tests/legacy-read-repository.test.mjs",
+  "scripts/dev/wsl/mysql-migration-roundtrip.sh",
   "database/migrations/2026061601_m01b_core_schema.up.sql",
   "database/migrations/2026061601_m01b_core_schema.down.sql",
   "database/migrations/2026061601_m01b_core_schema.verify.sql",
@@ -31,6 +33,11 @@ foreach ($path in $requiredFiles) {
   }
 }
 
+$packageJson = Get-Content "backend/package.json" -Raw | ConvertFrom-Json
+if (-not $packageJson.scripts.'test:mysql:migration') {
+  throw "backend/package.json is missing test:mysql:migration"
+}
+
 & npm --prefix backend test
 if ($LASTEXITCODE -ne 0) {
   throw "backend contract test failed"