v1.6.8: remove offer exchange rate, add invoice item description, offer filters, table animations

- Remove exchange_rate and exchange_rate_date from quotations (schema, service, PDF, form)
- Add item_description field to invoice_items (schema, migration, service, form, PDF)
- Add offer status/customer/order filters with tab-based UI
- Clean up offer statuses to active/ordered/invalidated
- Allow invalidate action for non-ordered offers (not just expired)
- Add fade animations on offers and invoices table data changes

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/services/invoices.service.ts

@@ -23,6 +23,7 @@ const ALLOWED_SORT_FIELDS = [
 
 interface InvoiceItemInput {
   description?: string;
+  item_description?: string;
   quantity?: number;
   unit?: string;
   unit_price?: number;
@@ -374,6 +375,7 @@ export async function createInvoice(body: Record<string, any>) {
       data: (body.items as InvoiceItemInput[]).map((item, i) => ({
         invoice_id: invoice.id,
         description: item.description ?? null,
+        item_description: item.item_description ?? null,
         quantity: item.quantity ?? 1,
         unit: item.unit ?? null,
         unit_price: item.unit_price ?? 0,
@@ -471,6 +473,7 @@ export async function updateInvoice(id: number, body: Record<string, any>) {
         data: (body.items as InvoiceItemInput[]).map((item, i) => ({
           invoice_id: id,
           description: item.description ?? null,
+          item_description: item.item_description ?? null,
           quantity: item.quantity ?? 1,
           unit: item.unit ?? null,
           unit_price: item.unit_price ?? 0,