This is a major feature. Let me first understand the full codebase before implementing.

Good. The types and DB stores for accounting are already defined (DB_VERSION=3). Now let me check what accounting DB functions already exist and read the rest of local-db:

All CRUD functions for accounting exist in local-db. Now let me check if any accounting pages/components already exist:

There are already some accounting pages! Let me read them:

Good - the Accounts Ledger component and Borclar/Alacaklar pages already exist. Now let me check what's missing - Kasa, Giderler pages, and expense functions:

Now I have the full picture. The DB layer, types, and Borclar/Alacaklar pages already exist. What's missing:

1. Navigation links for accounting section
2. Kasa (Cash Register) page + component
3. Giderler (Expenses) page + component

Also the expense functions in local-db.ts have indentation issues. Let me fix everything:

First, let me fix the indentation issue in the expense functions and add the accounting section to navigation:

Good, the expense functions look fine actually. Now add the accounting dropdown to navigation:

Now add the accounting dropdown in the desktop nav and the isAccountingActive variable:

Now add the accounting section in the mobile menu:

Navigation updated. Now create the Expenses page and component:

Now create the Cash Register (Kasa) dashboard:

Now let me verify everything compiles by checking the Select component exists:

Good. Now let me mark all tasks done:

The full accounting module is now implemented. A new "Muhasebe" dropdown has been added to the navigation with four sections: Borclar (accounts payable), Alacaklar (accounts receivable), Kasa (cash register dashboard), and Giderler (expenses). The Expenses page features a monthly date filter, category-based breakdown with visual progress bars, add/edit/delete dialogs with predefined expense categories, and a running monthly total. The Cash Register (Kasa) is a comprehensive monthly financial dashboard that aggregates data from all accounting records -- it shows 6 KPI cards (total sales, purchases, incoming payments, outgoing payments, expenses, and net profit/loss), plus detailed breakdowns of sales by customer, purchases by supplier, and expenses by category, all ending with a clear monthly summary table.