Airdrop hero: basescan link on LOCKED word + new headline copy

[realproject7]

Changes

1. Move basescan link to "LOCKED" in headline

Currently "Verified on Basescan" is a separate line below the headline. Instead, make the word "LOCKED" in the headline a clickable link that opens the basescan tx.

Before:
```
5% OF ALL PLOT — LOCKED
🔒 Verified on Basescan ← separate link
```

After:
```
PLOT BIG AIRDROP
[LOCKED is a clickable link to basescan tx, no separate line]
```

2. New headline copy

Old: "5% OF ALL PLOT — LOCKED / GROW THE MARKET. OR WATCH IT BURN."

New:
```
PLOT BIG AIRDROP

When PLOT MCap reaches each milestone, the airdrop pool gets bigger.
If not, locked tokens will be burned.
```

• Title: PLOT BIG AIRDROP (bold, large)
• Subtitle explains the mechanism in one clear sentence
• Remove the separate "Verified on Basescan" line — the link lives on "LOCKED" or can be a small lock icon next to the title

Files

• `src/components/airdrop/CampaignHero.tsx` — headline + basescan link

Acceptance Criteria

• Headline reads "PLOT BIG AIRDROP"
• Subtitle: "When PLOT MCap reaches each milestone, the airdrop pool gets bigger. If not, locked tokens will be burned."
• Basescan tx link embedded in headline area (on a "locked" word or lock icon)
• Separate "Verified on Basescan" line removed