fix(frontend): extend multipart upload timeouts

[JYao-Chen]

Description

Large multipart uploads inherit the shared Axios 30-second timeout. On slower links, nginx may still be receiving or buffering the request body when the browser aborts, which surfaces as a generic network error even though the configured size limit allows the file.

This change:

• gives multipart uploads a one-hour Axios timeout while preserving per-call overrides;
• aligns nginx client_body_timeout with the existing one-hour API proxy timeouts.

Type of Change

• 🐛 Bug fix
• 🔧 Configuration / Build / CI

Related Issue

N/A

Testing

• npm run type-check
• npm run build
• rendered frontend/nginx.conf with the production entrypoint variables and ran nginx -t
• git diff --check origin/main...HEAD

Checklist

• git diff --check origin/main...HEAD passes
• Changed source files are formatted
• Targeted tests for the changed packages/components pass
• Diff-scoped lint passes where applicable
• Full-repository checks were run, or any unrelated/environment-dependent failures are documented above
• Self-reviewed the code
• Added/updated tests covering the change
• Updated related documentation
• Breaking changes are clearly called out in the description above

Screenshots / Recordings

N/A