Simplify parallel build flag evaluation

Use direct boolean check  to reduce
verbosity without changing behavior.

Author: PeterDaveHello

build.mjs

@@ -14,7 +14,7 @@ const outdir = 'build'
 const __dirname = path.resolve()
 const isProduction = process.argv[2] !== '--development' // --production and --analyze are both production
 const isAnalyzing = process.argv[2] === '--analyze'
-const parallelBuild = process.env.BUILD_PARALLEL === '0' ? false : true
+const parallelBuild = process.env.BUILD_PARALLEL !== '0'
 const isWatchOnce = !!process.env.BUILD_WATCH_ONCE
 // Cache compression control: default none; allow override via env
 const cacheCompressionEnv = process.env.BUILD_CACHE_COMPRESSION