feat: Coinbase banking integration (#388)
## Summary
Adds **Coinbase** as a banking/investment provider, alongside existing
Binance, Bitpanda, and Indexa Capital integrations. Connection auth uses
Coinbase Developer Platform (CDP) JWT (ES256) API keys.
Sync model mirrors Bitpanda: no historical balance reconstruction
(Coinbase API has no daily snapshot endpoint). Balance tracking starts
from connection date.
## Account model
One single **Crypto Portfolio** Whisper Account in the user's fiat
currency, aggregating all Coinbase wallets (crypto + fiat).
## Backend
- `app/Services/Banking/CoinbaseClient.php` — JWT-signed Coinbase
Advanced Trade client (`firebase/php-jwt` ES256). Per-request JWT, 120s
TTL, `uri` claim `"METHOD host/path"`. Methods:
`getAccounts`/`getAllAccounts` (cursor pagination), `getProduct`,
`getBestBidAsk` (batched), with 429 retry/backoff.
- `app/Services/Banking/CoinbaseBalanceSyncService.php` — Partitions
wallets into fiat vs crypto. Batched `best_bid_ask` for prices, USD
stablecoin shortcut (USDT/USDC/DAI/PYUSD/GUSD),
`CurrencyConversionService` fallback. Aggregates everything into user
fiat.
- `app/Http/Controllers/OpenBanking/CoinbaseController.php` +
`ConnectCoinbaseRequest.php` — mirror Bitpanda flow, validates
`api_key_name` (`organizations/{org}/apiKeys/{id}`) + PEM `private_key`.
Stores key_name in `api_token`, PEM in `api_secret` (already encrypted
TEXT).
- `BankingConnection::isCoinbase()`,
`SyncBankingConnectionJob::syncCoinbase()`, credential-update flow.
- `routes/web.php`: `POST /open-banking/coinbase/connect`.
- Bank seeder entry + factory `coinbase()` state.
## Frontend
- `connect-account-dialog.tsx` / `connect-account-inline.tsx`: Coinbase
appears in the bank picker. Confirm step shows `<Input>` for API key
name and `<Textarea>` (multi-line) for the PEM private key, with link to
CDP portal.
- `update-credentials-dialog.tsx`: Coinbase credentials editable.
- `settings/connections.tsx`: coinbase included in `isApiKeyProvider`.
- Wayfinder auto-generated `CoinbaseController.ts` +
`routes/open-banking/coinbase`.
## Tests
- `tests/Feature/OpenBanking/CoinbaseControllerTest.php` — happy path,
invalid creds (401 → 422), validation errors, subscription gate.
- `tests/Feature/OpenBanking/CoinbaseBalanceSyncTest.php` — mixed
crypto+fiat aggregation, USD stablecoin valuation, skip when
external_account_id missing.
All **217 OpenBanking tests pass**. Pint + ESLint clean.
## Follow-ups (not in this PR)
- Upload `storage/banks/logos/coinbase.png` to production storage (URL
referenced in seeder + frontend).
- Invested-amount calc from transaction history (deferred).
- Historical balance reconstruction (deferred — Coinbase has no daily
snapshot endpoint).
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