## Summary
Add support for the new `effective_balance_micros` field to show users
their effective balance accounting for pending charges.
## Changes
- **What**: Update balance display components to use
`effective_balance_micros` (with fallback to `amount_micros` for
backwards compatibility)
- **Types**: Add `pending_charges_micros` and `effective_balance_micros`
to `GetCustomerBalance` response type in registry-types
## Review Focus
- The fallback pattern ensures backwards compatibility if the API
doesn't return the new field
- The `effective_balance_micros` can be negative when pending charges
exceed the available balance
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7658-feat-support-effective_balance_micros-for-user-balance-display-2cf6d73d36508193a5a7e999f3185078)
by [Unito](https://www.unito.io)
