[T2.5d] /projection endpoint (canonical v5 contribution API)

[realproject7]

Epic: #1229 · Spec: §6.3 · Type: CODE · Estimate: 0.5 day · Depends on: T2.4b

Scope

GET /api/airdrop/projection?address=X
Auth: none (public read)
Response shape:
```json
{
"address": "0x...",
"buy_volume": 1234.5,
"qualified_refs": 3,
"has_fc_bonus": true,
"multiplier": 1.8,
"weighted_spend": 2222.1,
"community_total": 100000.0,
"projected_share": {
"bronze": 12.3,
"silver": 123.4,
"gold": 617.0,
"diamond": 1234.0
}
}
```

Implementation:

1. Select base columns for address from shared v_weighted_spend helper (T2.4b)
2. Read current FDV from pl_daily_prices to determine current milestone tier
3. Apply share = released_pool × (weighted_spend / community_total) for EACH milestone tier (Bronze/Silver/Gold/Diamond)
4. Return all 4 projected shares so UI can render the climb chart

Cache: 30s.

Canonical: This is the single v5 contribution API. /api/airdrop/points (T2.5f) becomes a deprecated thin shim.

Acceptance

• Returns 4 projected_share values for activated wallet
• Returns zeros for activated wallet with no buys
• Returns 404 / empty for non-activated wallet (per T2.4b filter — wallet excluded from v_weighted_spend)
• Cache 30s verified
• Output matches §4 worked example for the test fixture

Dependencies

T2.4b (shared SQL helper)

[realproject7]

Completed by PR #1283.