Make zip step more robust

Use once() listeners and a settled guard to avoid double resolution,
log non-fatal archiver warnings, and resolve on the write stream's
'finish' event to prevent truncated archives under I/O pressure.

Author: PeterDaveHello

build.mjs

@@ -434,10 +434,25 @@ async function zipFolder(dir) {
   await new Promise((resolve, reject) => {
     const output = fs.createWriteStream(zipPath)
     const archive = archiver('zip', { zlib: { level: 9 } })
-    const onError = (err) => reject(err)
-    output.on('error', onError)
-    archive.on('error', onError)
-    output.on('finish', resolve)
+    let settled = false
+    const fail = (err) => {
+      if (!settled) {
+        settled = true
+        reject(err)
+      }
+    }
+    output.once('error', fail)
+    archive.once('error', fail)
+    archive.on('warning', (err) => {
+      // Log non-fatal archive warnings for diagnostics
+      console.warn('[build][zip] warning:', err)
+    })
+    output.once('finish', () => {
+      if (!settled) {
+        settled = true
+        resolve()
+      }
+    })
     archive.pipe(output)
     archive.directory(dir, false)
     archive.finalize()