Update angular to 21

[saithis]

Upgrade to Angular 21 - updates the entire project from Angular 20 to Angular 21, including a migration from Karma/Jasmine to Vitest for testing and other tooling modernization.

Key changes:

• Angular 20 → 21: All @angular/* packages, @angular/cdk, @angular/material, angular-eslint, and CLI tooling updated to v21
• Karma/Jasmine → Vitest: Replaced @angular/build:karma test builder with @angular/build:unit-test (Vitest-based). Added @vitest/browser-playwright for browser testing. Removed karma.conf.js, test.ts, and polyfills-test.ts files
• Test migrations: All .spec.ts files updated from Jasmine syntax (beforeEach, jasmine.createSpy, etc.) to Vitest equivalents (vi.fn(), vi.spyOn(), etc.). Added test-setup.ts for global test configuration
• ESLint 9 → 10: Updated ESLint and removed eslint-plugin-jasmine
• Schematics tests → Vitest: Schematics tests now use Vitest via a dedicated vitest.config.schematics.ts instead of Jasmine
• Removed old schematic: Deleted the rename-prosoft-to-zvoove migration schematic (~2,500 lines)
• Zone.js removed: Dropped zone.js dependency (Angular 21 is zoneless-ready)
• Button component simplified: Refactored button.component.html template
• Minor bug fixes: Fixes in demo app, form component, select component, and table search component