Replace deprecated Angular directives (*ngFor, *ngIf) with modern Angular template syntax. Remove unused CommonModule imports across components for optimization. Clean up excess spacing and formatting in HTML files.

frontend/src/app/pages/particles/components/properties/properties.component.ts

@@ -2,7 +2,7 @@ import {Component} from '@angular/core';
 import {MatCard, MatCardContent, MatCardHeader, MatCardTitle} from "@angular/material/card";
 import {MatCheckbox} from "@angular/material/checkbox";
 import {MatFormField, MatInput, MatLabel} from "@angular/material/input";
-import {NgForOf} from "@angular/common";
+
 import {FormsModule, ReactiveFormsModule} from "@angular/forms";
 import {ParticleData, ParticleType} from '../../models/particle.model';
 import {MatSelect} from '@angular/material/select';
@@ -22,10 +22,9 @@ import {ParticleManagerService} from '../../services/particle-manager.service';
     MatLabel,
     MatOption,
     MatSelect,
-    NgForOf,
     ReactiveFormsModule,
     FormsModule
-  ],
+],
   templateUrl: './properties.component.html',
   styleUrl: './properties.component.scss'
 })