[Airdrop P3] Campaign status hero + milestone progress track

[realproject7]

Parent: #877
Depends on: #885

Scope

Build the hero section and milestone progress visualization for /airdrop page.

Hero Section (Section 1)

┌─────────────────────────────────────────────────┐
│  PLOT 10x Airdrop                               │
│  50,000 PLOT locked. Big or nothing.             │
│                                                 │
│  Time remaining: 142 days                       │
│  ████████████░░░░░░░░░░░░░░  38%               │
│                                                 │
│  Market Cap: $45,000                            │
│  ░░░░░░░░░░░░░░░░░░░░░░░░░  < Bronze ($1M)    │
│                                                 │
│  Pool value if Gold: $3,500,000                 │
└─────────────────────────────────────────────────┘

• Time progress bar (campaign start → end, % elapsed)
• Current MCap display (from /api/airdrop/status)
• MCap progress relative to milestone targets
• Pool value display at each milestone level
• Lockup proof link (link to Mint Club Locker on-chain tx)

Milestone Progress Track (Section 5)

Visual track: Bronze → Silver → Gold with mcap thresholds.

• Current mcap marker on the track
• Each milestone shows: target mcap, pool % unlocked, pool value at that price
• Clearly show which milestone is closest / achieved

Design

Follow PlotLink's existing design system (terminal/monospace aesthetic, cream/brown palette).

Files

• src/app/airdrop/page.tsx (page shell)
• src/components/airdrop/CampaignHero.tsx
• src/components/airdrop/MilestoneTrack.tsx

Acceptance Criteria

• Hero displays time remaining + progress bar
• Hero displays current mcap + progress toward milestones
• Pool value shown for each milestone tier
• Lockup proof link clickable (opens on-chain viewer)
• Milestone track visualizes Bronze/Silver/Gold with current position
• Responsive layout (mobile-first)
• Data from /api/airdrop/status