feat: add Vercel ignoreCommand to skip frontend builds on unrelated c…

[JemimahEkong]

Summary

Adds ignoreCommand to vercel.json to prevent unnecessary Vercel frontend builds when changes only affect backend or contracts.

Closes #1080

Changes

• Added:

"ignoreCommand": "git diff --quiet HEAD^ HEAD -- frontend/"

Behavior

• Skips Vercel builds when no files inside frontend/ are changed.
• Continues normal builds when frontend files are modified.

Verification

• Confirmed repo is a monorepo with separate frontend, backend, and contracts workspaces.
• No existing ignoreCommand was configured.
• No changes made to build/install commands.