Airdrop: update stale test-mode milestones to current prod values

[realproject7]

Problem

lib/airdrop/config.ts:55-67 has TEST_CONFIG.MILESTONES at the old values:

BRONZE:  { mcap: 7_000,  pct: 10 },
SILVER:  { mcap: 10_000, pct: 30 },
GOLD:    { mcap: 35_000, pct: 50 },
DIAMOND: { mcap: 50_000, pct: 100 },

The deployed Vercel environment runs with NEXT_PUBLIC_AIRDROP_MODE=test, so users currently see those stale numbers on https://plotlink.xyz/airdrop. The current canonical milestones (matching the "How does this work?" modal copy and PROD_CONFIG) are $1M / $10M / $50M / $100M.

Fix

Update TEST_CONFIG.MILESTONES in lib/airdrop/config.ts to match the prod values:

BRONZE:  { mcap: 1_000_000,   pct: 10 },
SILVER:  { mcap: 10_000_000,  pct: 30 },
GOLD:    { mcap: 50_000_000,  pct: 50 },
DIAMOND: { mcap: 100_000_000, pct: 100 },

Leave CAMPAIGN_START / CAMPAIGN_END / POOL_AMOUNT in TEST_CONFIG unchanged — the user only flagged the milestones as stale.

Acceptance criteria

• Test mode shows the same milestone values as prod ($1M / $10M / $50M / $100M).
• No other test-mode-specific config values change (dates, pool).
• No other hardcoded 7_000 / 35_000 references exist (verified — none).
• npm run typecheck and npm run lint pass.

Files

• lib/airdrop/config.ts