Frontend: deposit panel and rewards page need full integration testing

[alexanderkoh]

Description

The deposit panel and rewards page have been wired to real contract calls but need integration testing with a connected wallet.

Deposit Panel (components/campaign/deposit-panel.tsx)

• Verify buildJoinCampaign is called with correct params
• amount needs conversion to stroops (1e7)
• token address defaults to USDC — verify it's the correct SAC address
• campaignId is correctly parsed from the URL
• Show loading state during transaction
• Show success/error toast after submission
• Refresh campaign data after successful deposit

Rewards Page (app/rewards/page.tsx)

• buildClaim called with correct campaign ID
• Currently calls handleClaim(0) — needs to use actual campaign IDs from user positions
• Scan user positions across campaigns to show total claimable
• Show vesting progress (how much vested vs total)
• Handle partial claims correctly
• Refresh after successful claim