feat(bridge): Bridge banking in settings

[forge0x]

Summary

Establishes a single Bank accounts hub in Settings that unifies everything
bank-transfer related: money-in (your Flash USD receiving account) and
money-out (withdrawal banks). The user sees one place to receive by bank
transfer, add withdrawal accounts, and choose a default withdrawal account.

This supersedes and removes the original standalone "Account and routing number"
screen/row. The receiving account now lives inside the hub as the Receive card.

What's in this PR

1. Receive money

• Flash USD receiving account: bank name, account number, routing number
• Bridge KYC-gated locked state with an Upgrade your account CTA that opens the
  same AccountType upgrade flow as Home screen QuickStart
• reveal/copy account number, per-field copy actions, and copy-all
• Contact Support button opens the existing WhatsApp support URL

2. Withdraw to bank accounts

• BankAccountVM + useBankAccounts() normalize:
  • bridgeVirtualAccount -> single receive account
  • bridgeExternalAccounts (USD) -> Bridge withdrawal accounts
  • me.bankAccounts (local) -> local withdrawal accounts
• Withdraw accounts are grouped by currency with a per-currency default
• The default chosen in the hub is now used by:
  • Bridge cash-out account selection
  • local cash-out Withdraw to confirmation selector
• Add Bank Account supports a settings return path, so adding from the hub returns
  to the hub instead of dropping the user into the cash-out flow

3. PR cleanup / review pass

• deleted the orphaned standalone routing screen and settings row
• extracted the new Bank Accounts / Add Bank Account copy to i18n
• regenerated i18n source/types
• kept generated GraphQL unchanged

Interim vs. backend dependency

Bridge external accounts have no isDefault and no set-default mutation yet, so
the chosen default is persisted client-side in AsyncStorage for now. The storage
helpers are isolated in use-bank-accounts.ts so the frontend can swap to server
defaults in one place once the backend PR lands.

Backend PR for full best-case: lnflash/flash#423

• BridgeExternalAccount.isDefault: Boolean!
• bridgeSetDefaultExternalAccount(input:{ externalAccountId }): ...
• bridgeDeleteExternalAccount(input:{ externalAccountId }): ...
• later: bankAccountSetDefault / bankAccountCreate for local-rail parity

Until the backend mutations land, remove is still shown as "coming soon" and defaults
are client-side.

File-by-file

File	Change
app/screens/settings-screen/bank-accounts/types.ts	new normalized BankAccountVM / WithdrawGroup
app/screens/settings-screen/bank-accounts/use-bank-accounts.ts	normalized hook + interim default store/helpers
app/screens/settings-screen/bank-accounts/bank-accounts-screen.tsx	hub screen: Receive card + Withdraw list
app/screens/settings-screen/settings/bank-accounts.tsx	Settings row entry
app/screens/settings-screen/settings-screen.tsx	Bank accounts row replaces standalone routing row
app/components/topup-cashout-flow/CashoutWithdrawTo.tsx	reads hub-selected default for the confirmation selector
app/screens/topup-cashout-flow/CashoutDetails.tsx	uses hub-selected default for actual local/Bridge cash-out selection
app/screens/topup-cashout-flow/BridgeAddExternalAccount.tsx	cancel button, i18n, settings return path
app/navigation/*	add BankAccounts, remove orphaned BridgeAccountRouting
app/i18n/*	new Bank Accounts / Add Bank Account strings

Verification

• yarn tsc:check ✅
• targeted eslint on touched TS/TSX files ✅
• yarn check:translations ✅
• yarn check:codegen ✅
• yarn graphql-check ✅
• git diff --check ✅
• yarn test ⚠️ previously showed an existing unrelated failure in
  __tests__/screens/send-confirmation.spec.tsx

[islandbitcoin]

Pushed two commits to unblock this PR:

dfd006fa — merge feat/fygaro (conflict resolution). While this PR was open, #652 rewrote the same success-handler region of BridgeAddExternalAccount.tsx: it switched post-link navigation to navigation.replace (back-stack trap fix) and added an already-linked path that treats a duplicate submission (BRIDGE_API_ERROR) as success. A "take mine" resolution would have silently reverted that fix. Resolved by extracting a single navigateAfterLink helper used by both the success and already-linked alerts: returnTo: "BankAccounts" navigates back to the existing hub instance (form dropped from the stack), otherwise replace to CashoutDetails per #652. The already-linked path now also respects returnTo — adding a duplicate bank from Settings returns to Settings instead of dumping the user into the cash-out flow.

cb690e58 — small polish on top:

• extracted fix: bridge manual external account fallback #652's hardcoded already-linked alert strings to i18n (they predated this PR's i18n pass)
• toast confirmation when a default withdrawal account is set in the hub (there was no feedback beyond the radio moving)
• CashoutWithdrawTo reloads the stored default on screen focus instead of mount only, so a default changed in Settings shows up when returning to an already-mounted cash-out screen
• serverDefault is now a proper optional field on BankAccountVM instead of being smuggled through type casts

Verification on the merged tree (this repo's PR CI runs no typecheck or tests): yarn tsc:check clean, eslint clean on all touched files, yarn test green — 36 suites / 159 tests.

Deliberately NOT done here: wiring the backend #423 API (isDefault, bridgeSetDefaultExternalAccount, bridgeDeleteExternalAccount + GraphQL regen). That backend PR merged today, so the interim AsyncStorage default and the "Remove (coming soon)" toast can be replaced in a focused follow-up — the swap point is isolated in use-bank-accounts.ts as designed.

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