feat: add clock tick.

demo/Ursa.Demo/Pages/ClockDemo.axaml

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+<UserControl
+    x:Class="Ursa.Demo.Pages.ClockDemo"
+    xmlns="https://github.com/avaloniaui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:u="https://irihi.tech/ursa"
+    d:DesignHeight="450"
+    d:DesignWidth="800"
+    mc:Ignorable="d">
+    <Grid>
+        <u:ClockTicks
+            HorizontalAlignment="Stretch"
+            VerticalAlignment="Stretch"
+            HourTickWidth="4"
+            MinuteTickWidth="1"
+            HourTickForeground="Black"
+            MinuteTickForeground="Red" />
+    </Grid>
+</UserControl>

demo/Ursa.Demo/Pages/ClockDemo.axaml.cs

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+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace Ursa.Demo.Pages;
+
+public partial class ClockDemo : UserControl
+{
+    public ClockDemo()
+    {
+        InitializeComponent();
+    }
+}