refactor: remove InvoiceView component and update related email and invoice handling

- Deleted the InvoiceView component to streamline the codebase.
- Updated EmailPreview and SendEmailDialog components to include currency and notes fields.
- Enhanced invoice-form to handle default hourly rates and improved item mapping.
- Refactored email template generation to include notes and currency formatting.
- Adjusted API routers for invoices to calculate totals and handle notes and currency correctly.

src/server/api/routers/email.ts

@@ -105,6 +105,7 @@ export const emailRouter = createTRPCRouter({
           status: invoice.status,
           totalAmount: invoice.totalAmount,
           taxRate: invoice.taxRate,
+          currency: invoice.currency,
           notes: invoice.notes,
           client: {
             name: invoice.client.name,