Write `project.json` atomically to avoid metadata corruption on interruption

[kwannoel]

Summary

• src-tauri/src/storage.rs:135 overwrites project.json directly with fs::write(...).
• src-tauri/src/storage.rs:152 already contains corrupt-entry recovery because malformed project.json files are expected in the wild.

A crash or forced quit during save can leave truncated JSON on disk and make a project disappear behind the corrupt-entry path on the next load. Remediation: write to a temp file in the same directory, flush/fsync it, and rename it into place atomically so readers see either the old or new valid document, never a torn file.

Maintainer Metadata

• Fingerprint: atomic|corruption|data|filesystem|integrity|json|metadata|storage|write
• Symptom Type: metadata corruption
• Affected Files: src-tauri/src/storage.rs
• Keywords: storage, project_json, atomic_write, data_integrity, filesystem