Refactor AppSettingsDocument and CoeffSnapshotDocument: Remove LunchBreakHours property

Add CalendarEventDocument and CalendarEventType enum for event management

Update WorkDayDocument to include WorkUnitDocument and CalendarEventDocument lists

Enhance CouchbaseLiteWorkDayService with methods for managing WorkUnit and CalendarEvent

Revise MonthlySummaryModel to track preview worked hours and counted work units

Improve CSS for calendar view, including responsive design and new item styles

Domain/WorkUnitDocument.cs

@@ -0,0 +1,34 @@
+namespace WorkTracker.Domain;
+
+public sealed class WorkUnitDocument
+{
+    public string Id { get; set; } = string.Empty;
+
+    public string Label { get; set; } = "Work unit";
+
+    public WorkUnitLocation Location { get; set; } = WorkUnitLocation.Office;
+
+    public TimeOnly? StartTime { get; set; }
+
+    public TimeOnly? EndTime { get; set; }
+
+    public bool IsPreview { get; set; }
+
+    public decimal ManualWorkedHours { get; set; }
+
+    public decimal CalculatedWorkedHours { get; set; }
+
+    public decimal WorkedHoursDelta { get; set; }
+
+    public decimal GrossIncome { get; set; }
+
+    public decimal NetIncome { get; set; }
+
+    public string? Notes { get; set; }
+
+    public CoeffSnapshotDocument CoeffSnapshot { get; set; } = new();
+
+    public DateTimeOffset CreatedAtUtc { get; set; } = DateTimeOffset.UtcNow;
+
+    public DateTimeOffset UpdatedAtUtc { get; set; } = DateTimeOffset.UtcNow;
+}