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-year/calendar-year.html

@@ -1,17 +1,21 @@
 <div class="calendar-year">
 	@if (isLoading()) {
-	<div class="loading-overlay">
-		<div class="loading-spinner">
-			<mat-spinner></mat-spinner>
-			<p>Calcul en cours...</p>
+		<div class="loading-overlay">
+			<div class="loading-spinner">
+				<mat-spinner></mat-spinner>
+				<p>Calcul en cours...</p>
+			</div>
 		</div>
-	</div>
 	}
 	@for (month of months; track $index) {
-	<mat-card class="card">
-		<mat-card-content>
-			<app-calendar-month [monthIndex]="month" [year]="getYear(month)" [selectedDates]="selectedDates"></app-calendar-month>
-		</mat-card-content>
-	</mat-card>
+		<mat-card class="card">
+			<mat-card-content>
+				<app-calendar-month
+					[monthIndex]="month"
+					[year]="getYear(month)"
+					[selectedDates]="selectedDates"
+				></app-calendar-month>
+			</mat-card-content>
+		</mat-card>
 	}
 </div>