Upgrading to Angular 20:

Replaced checked in package-lock.json by regenerated one.
Ran ng update @angular/core@20 @angular/cli@20
Ran npm install @angular-builders/jest@^20.0.0 @fortawesome/angular-fontawesome@^3.0.0 @swimlane/ngx-graph@^11
Ran npm install ngx-mat-select-search@^8.0.2.
Ran ng update @angular/material@20.
Updated all eslint and typescript to the latest versions.
Removed @angular-devkit/schematics.
Updated fontawesome.
Updated rxjs and tslib.
Moved required node version from 16 to 20.
Updated jest-preset-angular.
Set preserveWhitespaces to false.
Corrected two type declarations in two typescript files to make ng serve run without errors.
Removed unused angular-devkit/schematics from view-user.component.ts .
Updated list of supported browsers.
Upgraded prettier.
Ran prettier . --write the first time.
Ran prettier . --write the second time.
Ran ng generate @angular/core:inject with defaults, excepted a handful of files.
Fixed remaining eslint problems.
Added dist directory to ignores in eslint.config.js.
Let prettier fix formatting, almost everything is just line breaks.
Made htmlhint ignore @if and @for Angular constructs.
Updated node version in Github workflow to 22.12.0 (build.yml).
Updated .env.ts.
Updated Angular datetime format strings from YYYY-MM-DD to yyyy-MM-dd.
Merged changes from dev into angular20 branch.

src/app/shared/theme-toggle/theme-toggle.component.ts

@@ -1,4 +1,4 @@
-import { Component, OnChanges, OnInit, SimpleChanges } from '@angular/core';
+import { Component, OnChanges, OnInit, SimpleChanges, inject } from '@angular/core';
 import { ThemingService } from './theming.service';
 import { SettingsService } from 'app/settings/settings.service';
 import { MatIconButton } from '@angular/material/button';
@@ -16,12 +16,10 @@ import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';
   ]
 })
 export class ThemeToggleComponent implements OnInit, OnChanges {
-  darkModeOn: boolean;
+  private themingService = inject(ThemingService);
+  private settingsService = inject(SettingsService);
 
-  constructor(
-    private themingService: ThemingService,
-    private settingsService: SettingsService
-  ) {}
+  darkModeOn: boolean;
 
   ngOnInit(): void {
     this.darkModeOn = !!this.settingsService.themeDarkEnabled;