fix(coinpay): read wallets whose chain field is a composite key like USDC_POL

[clawedassistant26]

Problem

A user who has connected CoinPay with the wallet:read scope, and who has active Global Wallet Addresses on CoinPayPortal, still gets an empty wallet list from ugig:

GET /api/coinpay/wallets
{"wallets":[],"oauth_required":false,"setup_required":true}

oauth_required: false shows the OAuth grant is fine, so the setup instructions ugig returns ("connect your CoinPay account", "paste those addresses into Settings > Global Wallet Addresses") send the user round a loop they cannot escape. Invoicing is blocked because the invoice route gates on workerWallets.length === 0.

Cause

getCoinpayGlobalWalletTokens reads wallets from CoinPayPortal's OIDC /api/oauth/userinfo. That endpoint returns each wallet as:

{ "address": "0x...", "chain": "USDC_POL", "label": "...", "business_id": "..." }

One composite token, USDC_POL, names both the coin and its chain. coinToPaymentCurrency only handles a bare symbol plus a separate chain field:

• directCurrency looks at currency, id and code, none of which are present, so it is empty.
• symbol falls through to coin.chain and becomes "USDC_POL", which matches none of the BTC / ETH / USDT / USDC branches.
• The function returns null, so normalizeGlobalWallets hits if (!currency || !address) continue and drops every wallet.

The same shape appears in the cryptocurrency column of merchant_wallets and business_wallets, so anything reading those rows directly is affected too. This became visible to more users after coinpayportal#197, which made userinfo return business wallets as well as account ones.

Fix

• compositeCurrencyKey resolves an identifier that is already a supported currency key containing an underscore (usdc_pol, usdt_pol, usdc_eth, ...). A composite match wins over a bare symbol found elsewhere on the record, because it carries the chain too.
• The symbol lookup now also considers cryptocurrency, and splits a symbol that carries its own chain suffix, so USDC-POLYGON and USDT_ETHEREUM resolve through the existing branches.
• The { symbol: "USDT", chain: "POL" } shape returned by /api/get-tokens is unchanged: a bare symbol splits to itself with no chain parts.

Tests

Added to src/lib/coinpayportal.test.ts:

• coinToPaymentCurrency resolves composite tokens, still resolves the bare symbol plus chain shape, splits a suffixed symbol, and returns null when nothing identifies the coin.
• getCoinpayGlobalWalletTokens normalizes a real userinfo payload into ["usdc_pol", "usdt_pol"], and still drops a wallet whose address fails validation for its chain.

The three new failing assertions reproduce the bug on master before the change (expected [] to deeply equal [ 'usdc_pol', 'usdt_pol' ]).

Full suite after the change: 1803 tests across 197 files pass, and tsc --noEmit is clean.