iOS EAS Build fails in "Prepare project" phase — tar: "Failed to restore metadata: File exists"

[jenns9-cloud]

All iOS EAS builds (preview, development, production profiles) fail during the "Prepare project" phase with:

app/_layout.tsx: Failed to restore metadata: File exists
tar: Error exit delayed from previous errors.

• EAS CLI: 18.0.5 / 18.0.6
• Expo SDK: 54
• Last successful iOS build: Feb 26, 2026 (same commit, same code)
• Android builds succeed with identical project
• Local Xcode builds succeed
• Tried: --clear-cache, clean prebuild, removing ios/ directory, .easignore, all three profiles
• Example build IDs: 9b2b8598-b0d6-4ab4-b3a2-00ad84c13bd2, ed6f67f5-8826-4885-86bd-ecc31fe14347, 025491d5-b7d2-4798-af77-b7207b099736

This appears related to #3421 (same "Unknown error" in Prepare project phase).