[Airdrop] Rename campaign to 'PLOT Big or Nothing Airdrop'

[realproject7]

Parent: #877

Change

Rename the campaign from "PLOT 10x Airdrop" to "PLOT Big or Nothing Airdrop" across all UI and code references.

Files to update

• src/components/airdrop/CampaignHero.tsx — main title
• src/app/airdrop/page.tsx — page title / metadata
• lib/airdrop/config.ts — if campaign name is stored there
• Any other component referencing "10x Airdrop"

Acceptance Criteria

• All references to "10x Airdrop" changed to "Big or Nothing Airdrop"
• Page title / meta tag updated
• Hero displays "PLOT Big or Nothing Airdrop"