Use case cards section: payroll, aid, airdrop, remittance

[phertyameen]

Issue #3: Use case cards section: payroll, aid, airdrop, remittance

Category: UI/Homepage
Repo: bridgelet (frontend + docs)

Description

Add a section below the hero showing 4 use case cards (payroll, aid disbursements, airdrops, remittances). Each card should have an icon, title, and 1-line description. Link each to a future /use-cases page.

Acceptance Criteria

• Implementation complete
• Tests passing
• Docs updated
• Reviewed and merged