## Summary
- Adds an optional balance input field to the account creation modal for
**investment**, **loan**, **retirement**, and **savings** account types.
- When a balance is provided, an `AccountBalance` record is created for
today's date upon account creation.
- The balance label adapts to the account type (e.g., "Owed Amount" for
loans, "Balance" for others).
## Changes
- **`account-form.tsx`** — Shows `AmountInput` when a balance-tracking
type is selected and currency is set.
- **`create-account-dialog.tsx`** — Passes `balance` in the POST payload
when present.
- **`StoreAccountRequest.php`** — Adds optional `balance` (nullable
integer) validation.
- **`AccountController::store`** — Creates an `AccountBalance` record
when balance is provided.
- **`AccountTest.php`** — 3 new tests covering creation with balance,
without balance, and invalid balance validation.
## Screenshots
<img width="1017" height="649" alt="image"
src="https://github.com/user-attachments/assets/4bf1530e-0faf-45a4-a3d1-d0ec49d5b412"
/>
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