Modernize CI/CD pipeline with comprehensive automation (#25)

* Initial plan

* Add comprehensive CI/CD workflows and tooling

- Add PR validation workflow with lint, format, type check, test, and build steps
- Improve Docker build workflow with caching, security scanning, and manual trigger
- Add CodeQL security analysis workflow
- Add Dependabot configuration for automated dependency updates
- Configure ESLint with TypeScript support
- Add npm scripts for linting and formatting
- Format code with Prettier
- Fix linting issues in source code

Co-authored-by: THoguet <61246905+THoguet@users.noreply.github.com>

* Update README and fix build configuration

- Add CI/CD documentation to README
- Document code quality tools and scripts
- Disable font optimization in production build to avoid network dependency
- Add build cache configuration for GitHub Actions

Co-authored-by: THoguet <61246905+THoguet@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: THoguet <61246905+THoguet@users.noreply.github.com>

src/app/components/calendar-settings/calendar-settings.spec.ts

@@ -3,22 +3,21 @@ import { provideZonelessChangeDetection } from '@angular/core';
 import { CalendarSettings } from './calendar-settings';
 
 describe('CalendarSettings', () => {
-  let component: CalendarSettings;
-  let fixture: ComponentFixture<CalendarSettings>;
+	let component: CalendarSettings;
+	let fixture: ComponentFixture<CalendarSettings>;
 
-  beforeEach(async () => {
-    await TestBed.configureTestingModule({
-      imports: [CalendarSettings],
-      providers: [provideZonelessChangeDetection()]
-    })
-    .compileComponents();
+	beforeEach(async () => {
+		await TestBed.configureTestingModule({
+			imports: [CalendarSettings],
+			providers: [provideZonelessChangeDetection()],
+		}).compileComponents();
 
-    fixture = TestBed.createComponent(CalendarSettings);
-    component = fixture.componentInstance;
-    fixture.detectChanges();
-  });
+		fixture = TestBed.createComponent(CalendarSettings);
+		component = fixture.componentInstance;
+		fixture.detectChanges();
+	});
 
-  it('should create', () => {
-    expect(component).toBeTruthy();
-  });
+	it('should create', () => {
+		expect(component).toBeTruthy();
+	});
 });

src/app/components/calendar-settings/calendar-settings.ts

@@ -1,7 +1,7 @@
 import { Component } from '@angular/core';
-import { MatButton, MatButtonModule } from '@angular/material/button';
+import { MatButtonModule } from '@angular/material/button';
 import { MatDialog } from '@angular/material/dialog';
-import { MatIcon, MatIconModule } from '@angular/material/icon';
+import { MatIconModule } from '@angular/material/icon';
 import { CalendarSettingsDialog } from '../dialog/calendar-settings-dialog/calendar-settings-dialog';
 import { MatDividerModule } from '@angular/material/divider';