v1.6.9: cleanup offer dead columns, add item template picker to offer form

- Remove dead DB columns: uuid, sync_version from quotations/quotation_items/scope_sections; is_deleted from quotation_items/scope_sections; content_editor_height from scope_sections
- Remove unused scope_title/scope_description from offer form state
- Remove dead CSS: offers-template-menu, offers-draft-indicator, exchange-rate
- Remove dead scope_title translation key from offers PDF
- Fix duplicate Customer interface in OfferDetail.tsx (use shared type)
- Add missing title field to ScopeTemplate interface
- Add item template picker dropdown next to "Přidat položku" button

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

src/routes/admin/offers-pdf.ts

@@ -186,7 +186,6 @@ function buildAddressLines(
 
 const TRANSLATIONS: Record<string, Record<string, string>> = {
   title: { EN: "PRICE QUOTATION", CZ: "CENOV\u00C1 NAB\u00CDDKA" },
-  scope_title: { EN: "SCOPE OF THE PROJECT", CZ: "ROZSAH PROJEKTU" },
   valid_until: { EN: "Valid until", CZ: "Platnost do" },
   customer: { EN: "Customer", CZ: "Z\u00E1kazn\u00EDk" },
   supplier: { EN: "Supplier", CZ: "Dodavatel" },
@@ -571,12 +570,6 @@ ${indentCSS}
     border-bottom: 2.5pt solid #de3a3a;
     padding-bottom: 1mm;
   }
-  .totals .exchange-rate {
-    text-align: right;
-    font-size: 7.5pt;
-    color: #969696;
-    margin-top: 3mm;
-  }
 
   /* ---- Scope sections ---- */
   .scope-page {