CUB-41: Add low stock indicators to filament UI

frontend/src/app/components/dashboard-summary/dashboard-summary.component.ts

@@ -0,0 +1,80 @@
+import { ChangeDetectionStrategy, Component, Input, OnDestroy, signal, computed } from '@angular/core';
+import { CommonModule } from '@angular/common';
+import { MatButtonModule } from '@angular/material/button';
+import { MatIconModule } from '@angular/material/icon';
+import { MatChipsModule } from '@angular/material/chips';
+import { MatTooltipModule } from '@angular/material/tooltip';
+import { AgentSummary, SystemHealth } from '../../models/agent.model';
+
+@Component({
+  selector: 'app-dashboard-summary',
+  standalone: true,
+  imports: [
+    CommonModule,
+    MatButtonModule,
+    MatIconModule,
+    MatChipsModule,
+    MatTooltipModule,
+  ],
+  templateUrl: './dashboard-summary.component.html',
+  styleUrls: ['./dashboard-summary.component.scss'],
+  changeDetection: ChangeDetectionStrategy.OnPush,
+})
+export class DashboardSummaryComponent implements OnDestroy {
+  /** Agent summary data — reactive signal, updatable via updateSummary() */
+  readonly summary = signal<AgentSummary>({
+    total: 0,
+    active: 0,
+    idle: 0,
+    thinking: 0,
+    error: 0,
+  });
+
+  /** System health data — reactive signal, updatable via updateHealth() */
+  readonly health = signal<SystemHealth>({
+    connected: false,
+    status: 'down',
+  });
+
+  /** Computed signal: whether there are errors to highlight */
+  readonly hasErrors = computed(() => this.summary().error > 0);
+
+  /** Computed signal: whether system is degraded */
+  readonly isDegraded = computed(() => this.health().status === 'degraded');
+
+  /** Computed signal: whether system is down */
+  readonly isDown = computed(() => this.health().status === 'down');
+
+  /** Computed signal: connection indicator color */
+  readonly connectionColor = computed(() =>
+    this.health().connected ? 'connected' : 'disconnected'
+  );
+
+  /** Computed signal: overall status label */
+  readonly statusLabel = computed(() => {
+    const h = this.health();
+    if (h.status === 'healthy') return 'All Systems Go';
+    if (h.status === 'degraded') return 'Degraded';
+    return 'Offline';
+  });
+
+  /**
+   * Update the agent summary. Called by the parent or a service
+   * when new data arrives (e.g., via SignalR).
+   */
+  updateSummary(data: AgentSummary): void {
+    this.summary.set(data);
+  }
+
+  /**
+   * Update the system health. Called by the parent or a service
+   * when the connection state changes.
+   */
+  updateHealth(data: SystemHealth): void {
+    this.health.set(data);
+  }
+
+  ngOnDestroy(): void {
+    // Cleanup handled by signals — no manual subscription teardown needed
+  }
+}