[codex] Add live work proof section

[kgy7247]

Summary

• Add a LiveWorkProof landing-page section that surfaces currently funded Gibwork tasks before sign-in.
• Fetch the public marketplace feed with a 15-minute revalidation window and fall back to curated examples if the feed is unavailable.
• Add a short contributor proof loop so visitors understand how task evidence moves from task selection to sponsor review.

Closes #124.

Why

The landing page explains the marketplace, but new contributors still need a faster way to see concrete, active work and understand what proof a good submission should include. This section makes the marketplace feel current without requiring a broad page redesign.

Safeguards

• Hidden, closed, and zero-remaining tasks are excluded.
• The live feed avoids investment-style promotional tasks with risky claims such as guaranteed profit language.
• Each card links to the task detail page and keeps the mobile layout compact.

Validation

• npm run build passed.
• npm run lint could not run as a non-interactive check because the repo currently prompts to configure ESLint via next lint.

[vercel]

@kgy7247 is attempting to deploy a commit to the gibwork Team on Vercel.

A member of the Team first needs to authorize it.

[kgy7247]

Validation update: the Vercel status currently points to the team fork-authorization flow, not to a local build failure. I rechecked the PR state today: it remains open, ready for review, and mergeable. Local validation performed for the submitted branch:
pm run build passed;
pm run lint is not a usable non-interactive check in this repo because it prompts to configure ESLint.