## What
In the add-transaction modal, the **Update account balance** checkbox
now defaults to **on**. An explicit opt-out is still remembered in
`localStorage`, so users who turned it off keep their preference.
Balance updates also move from the client to the backend, mirroring the
existing delete flow
(`ManualBalanceAdjuster::reverseDeletedTransaction`).
## How the balance is applied
When the toggle is on, `TransactionController::store` calls the new
`ManualBalanceAdjuster::applyCreatedTransaction`, which adjusts the
balance on the **transaction's own date**:
- A balance already on that date → increased by the transaction amount.
- No balance on that date but an earlier one exists → a new balance for
that date is created from the **closest earlier balance** plus the
amount.
- No prior balances at all (first transaction on the account) → the
balance is set to the transaction amount.
Connected accounts are skipped, since their balances come from bank
sync.
## Why
The previous client-side flow fetched all balances, computed from the
**latest balance overall** (not the transaction's date), and stored via
a separate request. This replaces those three round-trips with one
atomic server-side write and fixes the wrong base balance.
## Tests
- Feature tests for all three balance cases plus the not-requested and
connected-account guards (`tests/Feature/TransactionTest.php`).
- Frontend test asserting the toggle is checked by default in create
mode.
Full suite green locally: Pest (1690 passed), vitest (221 passed), Pint,
ESLint, Prettier.
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