feat(diagnostics): add health engine

src/app/features/diagnostics/services/diagnostics-logger.service.ts

@@ -0,0 +1,17 @@
+import { Injectable, signal } from '@angular/core';
+import { DiagnosticEntry } from '../models/diagnostics.model';
+
+@Injectable({ providedIn: 'root' })
+export class DiagnosticsLoggerService {
+  private readonly logsState = signal<DiagnosticEntry[]>([]);
+
+  readonly logs = this.logsState.asReadonly();
+
+  log(entry: DiagnosticEntry): void {
+    this.logsState.update(current => [entry, ...current].slice(0, 300));
+  }
+
+  clear(): void {
+    this.logsState.set([]);
+  }
+}