Add installed items count API, installed items button, and menu reorder

- Add getInstalledItemsCount endpoint through full stack (controller → DAO)
  with optional itemType filter
- Add getInstalledItemsCount to UI IotHubApiService
- Home page: show "Installed Items: N" stroked button at top-right when
  count > 0, white bg, primary border, card shadow; navigates to installed items
- Count updates on install/delete via API re-fetch and local decrement
- Move IoT Hub menu item right after Dashboards in sidebar

application/src/main/java/org/thingsboard/server/controller/IotHubController.java

@@ -87,6 +87,13 @@ public class IotHubController extends BaseController {
         return iotHubInstalledItemService.findByTenantId(getTenantId(), itemType, pageLink);
     }
 
+    @PreAuthorize("hasAuthority('TENANT_ADMIN')")
+    @GetMapping("/installedItems/count")
+    @ResponseBody
+    public long getInstalledItemsCount(@RequestParam(required = false) String itemType) throws ThingsboardException {
+        return iotHubInstalledItemService.countByTenantId(getTenantId(), itemType);
+    }
+
     @PreAuthorize("hasAuthority('TENANT_ADMIN')")
     @GetMapping("/installedItems/itemIds")
     @ResponseBody

dao/src/main/java/org/thingsboard/server/dao/iot_hub/IotHubInstalledItemDao.java

@@ -30,6 +30,8 @@ public interface IotHubInstalledItemDao extends Dao<IotHubInstalledItem> {
 
     List<UUID> findInstalledItemIdsByTenantId(TenantId tenantId);
 
+    long countByTenantId(TenantId tenantId, String itemType);
+
     void deleteByTenantId(TenantId tenantId);
 
 }

dao/src/main/java/org/thingsboard/server/dao/iot_hub/IotHubInstalledItemService.java

@@ -34,6 +34,8 @@ public interface IotHubInstalledItemService {
 
     List<UUID> findInstalledItemIdsByTenantId(TenantId tenantId);
 
+    long countByTenantId(TenantId tenantId, String itemType);
+
     void deleteById(TenantId tenantId, IotHubInstalledItemId id);
 
     void deleteByTenantId(TenantId tenantId);

dao/src/main/java/org/thingsboard/server/dao/iot_hub/IotHubInstalledItemServiceImpl.java

@@ -55,6 +55,11 @@ class IotHubInstalledItemServiceImpl implements IotHubInstalledItemService {
         return iotHubInstalledItemDao.findInstalledItemIdsByTenantId(tenantId);
     }
 
+    @Override
+    public long countByTenantId(TenantId tenantId, String itemType) {
+        return iotHubInstalledItemDao.countByTenantId(tenantId, itemType);
+    }
+
     @Override
     public void deleteById(TenantId tenantId, IotHubInstalledItemId id) {
         iotHubInstalledItemDao.removeById(tenantId, id.getId());

dao/src/main/java/org/thingsboard/server/dao/sql/iot_hub/IotHubInstalledItemRepository.java

@@ -43,6 +43,13 @@ interface IotHubInstalledItemRepository extends JpaRepository<IotHubInstalledIte
             """)
     Page<IotHubInstalledItemEntity> findByTenantId(@Param("tenantId") UUID tenantId, @Param("itemType") String itemType, @Param("textSearch") String textSearch, Pageable pageable);
 
+    @Query("""
+            SELECT COUNT(item) FROM IotHubInstalledItemEntity item
+            WHERE item.tenantId = :tenantId
+              AND (:itemType IS NULL OR item.itemType = :itemType)
+            """)
+    long countByTenantId(@Param("tenantId") UUID tenantId, @Param("itemType") String itemType);
+
     @Transactional
     @Modifying
     @Query(value = "DELETE FROM iot_hub_installed_item WHERE tenant_id = :tenantId", nativeQuery = true)

dao/src/main/java/org/thingsboard/server/dao/sql/iot_hub/JpaIotHubInstalledItemDao.java

@@ -57,6 +57,11 @@ class JpaIotHubInstalledItemDao extends JpaAbstractDao<IotHubInstalledItemEntity
         return repository.findInstalledItemIdsByTenantId(tenantId.getId());
     }
 
+    @Override
+    public long countByTenantId(TenantId tenantId, String itemType) {
+        return repository.countByTenantId(tenantId.getId(), itemType);
+    }
+
     @Override
     public void deleteByTenantId(TenantId tenantId) {
         repository.deleteByTenantId(tenantId.getId());

ui-ngx/src/app/core/http/iot-hub-api.service.ts

@@ -150,6 +150,14 @@ export class IotHubApiService {
     );
   }
 
+  public getInstalledItemsCount(itemType?: string, config?: IotHubRequestConfig): Observable<number> {
+    let url = '/api/iot-hub/installedItems/count';
+    if (itemType) {
+      url += `?itemType=${itemType}`;
+    }
+    return this.http.get<number>(url, { params: this.buildParams(config) });
+  }
+
   public deleteInstalledItem(installedItemId: string, config?: IotHubRequestConfig): Observable<void> {
     return this.http.delete<void>(
       `/api/iot-hub/installedItems/${installedItemId}`,

ui-ngx/src/app/modules/home/pages/iot-hub/iot-hub-home.component.html

@@ -16,6 +16,14 @@
 
 -->
 <div class="tb-iot-hub-home">
+  <!-- Installed Items button -->
+  @if (installedItemsCount > 0) {
+    <button mat-stroked-button color="primary" class="tb-iot-hub-installed-btn" (click)="navigateToInstalledItems()">
+      <mat-icon>inventory_2</mat-icon>
+      {{ 'iot-hub.installed-items' | translate }}: {{ installedItemsCount }}
+    </button>
+  }
+
   <!-- Hero section -->
   <div class="tb-iot-hub-hero">
     <!-- Background gradient overlay -->

ui-ngx/src/app/modules/home/pages/iot-hub/iot-hub-home.component.scss

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+@import "../../../../../scss/constants";
+
 // Outer page — 16px padding around the white container
 :host {
   display: block;
@@ -43,12 +45,26 @@
     z-index: 0;
   }
 
-  > * {
+  > *:not(.tb-iot-hub-installed-btn) {
     position: relative;
     z-index: 1;
   }
 }
 
+// Installed Items button — Design: top-right, white bg, primary border, card shadow
+.tb-iot-hub-installed-btn {
+  position: absolute;
+  top: 24px;
+  right: 24px;
+  z-index: 2;
+  background: white;
+  box-shadow: 0 1px 4px 0 rgba(0, 0, 0, 0.08), 0 4px 8px 0 rgba(0, 0, 0, 0.08);
+
+  &.mat-primary {
+    --mat-button-outlined-outline-color: #{$tb-primary-color};
+  }
+}
+
 // Hero section
 .tb-iot-hub-hero {
   text-align: center;

ui-ngx/src/app/modules/home/pages/iot-hub/iot-hub-home.component.ts

@@ -106,6 +106,7 @@ export class TbIotHubHomeComponent implements OnInit, OnDestroy {
 
   installedWidgets: IotHubInstalledItem[] = [];
   installedSolutionTemplates: IotHubInstalledItem[] = [];
+  installedItemsCount = 0;
 
   isLoading = true;
 
@@ -187,6 +188,9 @@ export class TbIotHubHomeComponent implements OnInit, OnDestroy {
   private reloadInstalledItems(type: ItemType): void {
     const config = { ignoreLoading: true };
     const pageLink = new PageLink(10000, 0);
+    this.iotHubApiService.getInstalledItemsCount(null, config).subscribe(count => {
+      this.installedItemsCount = count;
+    });
     if (type === ItemType.WIDGET) {
       this.iotHubApiService.getInstalledItems(pageLink, ItemType.WIDGET, config).subscribe(data => {
         this.installedWidgets = data.data;
@@ -250,6 +254,7 @@ export class TbIotHubHomeComponent implements OnInit, OnDestroy {
     dialogRef.afterClosed().subscribe(confirmed => {
       if (confirmed) {
         this.iotHubApiService.deleteInstalledItem(installedItem.id.id).subscribe(() => {
+          this.installedItemsCount = Math.max(0, this.installedItemsCount - 1);
           if (item.type === ItemType.WIDGET) {
             this.installedWidgets = this.installedWidgets.filter(i => i.id.id !== installedItem.id.id);
           } else if (item.type === ItemType.SOLUTION_TEMPLATE) {
@@ -281,7 +286,8 @@ export class TbIotHubHomeComponent implements OnInit, OnDestroy {
       calcFields: this.iotHubApiService.getPublishedVersions(buildQuery(ItemType.CALCULATED_FIELD, 6), config),
       ruleChains: this.iotHubApiService.getPublishedVersions(buildQuery(ItemType.RULE_CHAIN, 6), config),
       installedWidgets: this.iotHubApiService.getInstalledItems(installedPageLink, ItemType.WIDGET, config),
-      installedSolutionTemplates: this.iotHubApiService.getInstalledItems(installedPageLink, ItemType.SOLUTION_TEMPLATE, config)
+      installedSolutionTemplates: this.iotHubApiService.getInstalledItems(installedPageLink, ItemType.SOLUTION_TEMPLATE, config),
+      installedCount: this.iotHubApiService.getInstalledItemsCount(null, config)
     }).subscribe({
       next: (results) => {
         this.popularWidgets = results.widgets.data;
@@ -291,6 +297,7 @@ export class TbIotHubHomeComponent implements OnInit, OnDestroy {
         this.popularRuleChains = results.ruleChains.data;
         this.installedWidgets = results.installedWidgets.data;
         this.installedSolutionTemplates = results.installedSolutionTemplates.data;
+        this.installedItemsCount = results.installedCount;
         this.isLoading = false;
       },
       error: () => {