feat: enhance loading spinner with progress indication and add warnin… (#49)

* feat: enhance loading spinner with progress indication and add warning for unplaced vacation days

* Update src/app/services/calendar-service.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/app/components/calendar-year/calendar-year.scss

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/app/components/user-input/user-input.html

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Fix setTimeout async anti-pattern in calendar-year component (#50)

* Initial plan

* fix: replace setTimeout async anti-pattern with queueMicrotask and void

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

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

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <198982749+Copilot@users.noreply.github.com>

src/app/components/user-input/user-input.html

@@ -14,5 +14,16 @@
 			<input matInput type="number" max="365" min="0" formControlName="Others" />
 		</mat-form-field>
 	</form>
+	@if (hasRemainingDays()) {
+		<mat-card class="mat-elevation-z2 warning-card">
+			<mat-card-content class="warning-content">
+				<mat-icon color="warn" aria-hidden="true">warning</mat-icon>
+				<span>
+					{{ remainingDays() }} jour{{ remainingDays() > 1 ? 's' : '' }} de vacances non
+					placé{{ remainingDays() > 1 ? 's' : '' }}. Veuillez les placer manuellement.
+				</span>
+			</mat-card-content>
+		</mat-card>
+	}
 	<app-calendar-settings></app-calendar-settings>
 </div>