Refactor dashboard sections: KPI cards, filters, fallbacks

- Replace 4 static KPI cards with 5 interactive cards
  - 'Otvoreni nalozi' and 'Servisi danas' are now clickable links
  - Added context-aware subtotals (u kontekstu) when crane context is set
  - Replaced 'Upozorenja' (mileage-based, irrelevant for cranes) with 'Bez putnog naloga'
  - 'Dovrseni nalozi' now shows completion percentage
  - Added new card 'Moji zadaci danas' (tasks assigned to current user, today)
- Added crane context filter toggle on the tasks table (Sve dizalice / Odabrani kontekst)
- Service records page now shows last 10 records as fallback when no crane context is selected
- Moved SyncLogPanel into a collapsible <details> element
- Removed dead code: PAGE_MODE_TO_SECTION, activeSection/setActiveSection state,
  navbar:navigate event handler, and DashboardTopbar nav tab block (showSectionNav
  was always false; navigation is handled by Navbar.jsx)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/src/stores/fleetDashboardStore.js

@@ -464,16 +464,19 @@ export const $dashboardStats = computed(
         const servicesToday = tasks.filter(
             (t) => t.scheduled_date === today && (t.status === 'aktivan' || t.status === 'servis')
         ).length;
-        const warnings = serviceRecords.filter((record) => {
-            if (record.next_service_due_at == null || record.mileage == null) return false;
-            return Number(record.next_service_due_at) - Number(record.mileage) <= 1000;
-        }).length;
+        const totalWorkOrders = workOrders.length;
+        // Aktivni taskovi bez dodijeljenog putnog naloga
+        const tasksWithoutWorkOrder = tasks.filter(
+            (t) => (t.status === 'aktivan' || t.status === 'servis' || t.status === 'spreman_za_zavrsetak')
+                && !t.work_order
+        ).length;
 
         return {
             openWorkOrders,
             closedWorkOrders,
+            totalWorkOrders,
             servicesToday,
-            warnings,
+            tasksWithoutWorkOrder,
         };
     }
 );