Airdrop: rename FDV to MCap across all airdrop UI

[realproject7]

Problem

"FDV" (Fully Diluted Valuation) is crypto jargon that most users don't understand. The airdrop page uses FDV everywhere — milestone targets, burn bar, status display, milestone rows. Should use "MCap" (Market Cap) which is far more widely understood.

Context

PLOT's MCap calculation is actually FDV-based: `price × 1,000,000 (max supply)`. This is because PLOT has a fixed max supply with no inflation, so FDV = MCap in practice.

Solution

1. Replace all user-facing "FDV" labels with "MCap"
2. Add a one-time explanation somewhere unobtrusive (tooltip or footnote): "MCap = PLOT price × 1M max supply"
3. Keep internal variable names as-is (`currentFdv`, `mcap` in config) — this is a display-only change

Files to update

• `src/components/airdrop/CampaignHero.tsx` — burn bar labels, milestone rows, current FDV display
• `src/components/airdrop/MilestoneTrack.tsx` (if not deleted by Airdrop: redesign hero — bold 'Growing Pool' concept with burn visualization #1011)
• `src/components/airdrop/UserPoints.tsx` — estimated airdrop tooltips
• `src/components/airdrop/InnovationBanner.tsx` — summary paragraph
• `src/components/airdrop/ClaimPanel.tsx` — if FDV is referenced
• API response labels can stay as `currentFdv` internally

Acceptance Criteria

• All user-facing "FDV" replaced with "MCap"
• One explanation of MCap calculation (tooltip or footnote)
• No changes to API contracts or internal variable names
• Consistent terminology across all airdrop components