CI: bundle size budget guard

[0xMegie]

Area: apps/web, CI workflow

Goal: Prevent accidental large bundle regressions.

Tasks:

• Add a build-output size check with a documented budget.
• Fail when a chunk exceeds the agreed threshold.
• Document how to update budgets intentionally.

Acceptance:

• bun run --cwd apps/web build succeeds and the size check runs.
• Budgets are documented and not set below current output.

[helenahelenavanbeek-png]

I would like to work on this issue. I have experience with Rust and Soroban smart contract development. I will follow the acceptance criteria and add tests. Excited to contribute. Kindly assign.

[pablowizzy24]

A CI bundle size budget guard automatically checks your app's bundle size during builds and fails the build if it exceeds a set limit, helping keep the application fast and lightweight.