## Problem
Enable Banking issues **new account UIDs** (`external_account_id`) with
every new session. On reconnect, `AuthorizationController::callback()`
was correctly updating `session_id` on the `banking_connections` table
but **never refreshing `external_account_id` on child accounts**.
When the background `SyncBankingConnectionJob` ran after a reconnect, it
called `GET /accounts/{old-uid}/transactions` using stale UIDs from the
expired session, causing Enable Banking to return `401 EXPIRED_SESSION`
— surfaced to users as _"Authentication failed. Your credentials may
have expired or been revoked."_
## Changes
- **`AuthorizationController`** — added `refreshAccountIds()` private
method, called in the reconnect branch after `session_id` is updated and
before the sync job is dispatched. Matches existing accounts by **IBAN
first**, falls back to **positional order** (`created_at ASC`) for
legacy accounts without a stored IBAN.
- **`AuthorizationController`** — `createAccountsFromSession()` and
`createAccountsFromPending()` now persist the `iban` field on account
creation so future reconnects can use IBAN matching.
- **`Account` model** — `iban` added to `$fillable`.
- **Migration** — adds nullable `iban` column to `accounts` table.
## Tests
4 new feature tests in `AuthorizationControllerTest`:
- `reconnect callback updates external_account_id when enable banking
issues new account uids`
- `reconnect callback matches accounts by iban before falling back to
position`
- `reconnect callback uses positional fallback for accounts without
stored iban`
- `callback stores iban when creating accounts for the first time`
## Deploy notes
Run the migration after deploying:
```
php artisan migrate --force
```
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