Add Small and Large size variants to date/time picker controls

[Copilot]

Date/time picker controls lacked size variants, causing height misalignment when horizontally positioned with TextBox and NumericIntUpDown that support .Small and .Large classes.

Changes

Added .Small and .Large style selectors to:

• DatePicker
• TimePicker
• DateTimePicker
• DateRangePicker
• TimeRangePicker

Each selector sets MinHeight using existing TextBoxSmallHeight and TextBoxLargeHeight resources, matching the pattern in NumericUpDown.

Usage

<Grid ColumnDefinitions="Auto,100,Auto,100" ColumnSpacing="8">
    <TextBlock Grid.Column="0" Text="Date" />
    <u:DatePicker Grid.Column="1" Classes="Small" />
    <TextBlock Grid.Column="2" Text="Time" />
    <u:TimePicker Grid.Column="3" Classes="Small" />
</Grid>

Controls now align correctly with adjacent small-sized inputs.

Warning

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  • Triggering command: /usr/share/dotnet/dotnet dotnet exec --runtimeconfig /home/REDACTED/.nuget/packages/avalonia.buildservices/11.3.1/tools/netstandard2.0/runtimeconfig.json /home/REDACTED/.nuget/packages/avalonia.buildservices/11.3.1/tools/netstandard2.0/Avalonia.BuildServices.Collector.dll (dns block)

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Original prompt

---

This section details on the original issue you should resolve

<issue_title>DatePicker / TimePicker / DateTimePicker 应该添加 Small 样式类</issue_title>
<issue_description>当前 DatePicker / TimePicker / DateTimePicker 控件没有 Small 样式类, 当他们和 TextBox 水平排列时, 高度会不一致.

<Grid Grid.Column="1" ColumnDefinitions="Auto,100,Auto,100,Auto,100,Auto,100,Auto,100" ColumnSpacing="8" VerticalAlignment="Center">
    <TextBlock Grid.Column="0" VerticalAlignment="Center" Text="Item1" />
    <TextBox Grid.Column="1" Classes="Small" Text="Item1" />
    <TextBlock Grid.Column="2" VerticalAlignment="Center" Text="Item2" />
    <u:NumericIntUpDown Grid.Column="3" Classes="Small" Value="1" ShowButtonSpinner="False" />
    <TextBlock Grid.Column="4" VerticalAlignment="Center" Text="Item3" />
    <u:DatePicker Grid.Column="5" Classes="Small" HorizontalAlignment="Stretch" />
    <TextBlock Grid.Column="6" VerticalAlignment="Center" Text="Item4" />
    <u:TimePicker Grid.Column="7" Classes="Small" HorizontalAlignment="Stretch" />
    <TextBlock Grid.Column="8" VerticalAlignment="Center" Text="Item5" />
    <u:DateTimePicker Grid.Column="9" Classes="Small" HorizontalAlignment="Stretch" />
</Grid>

</issue_description>

<agent_instructions>Please add style for DatePicker, TimePicker, DateTimePicker, DateRangePicker, TimeRangePicker.
similar to

        <Style Selector="^.Large">
            <Setter Property="MinHeight" Value="{DynamicResource TextBoxLargeHeight}" />
        </Style>
        <Style Selector="^.Small">
            <Setter Property="MinHeight" Value="{DynamicResource TextBoxSmallHeight}" />
        </Style>
```</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes DatePicker / TimePicker / DateTimePicker 应该添加 Small 样式类 #876

---

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[Copilot]

Pull request overview

Adds .Small and .Large size variants for Semi theme date/time picker controls so they can align in height with other inputs (e.g., TextBox, NumericIntUpDown) when laid out horizontally.

Changes:

• Added .Small and .Large style selectors to set MinHeight on Date/Time picker-related controls.
• Standardized sizing to use TextBoxSmallHeight / TextBoxLargeHeight resources across these pickers.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Ursa.Themes.Semi/Controls/DatePicker.axaml	Adds .Small/.Large selectors to override MinHeight for DatePicker.
src/Ursa.Themes.Semi/Controls/TimePicker.axaml	Adds .Small/.Large selectors to override MinHeight for TimePicker.
src/Ursa.Themes.Semi/Controls/DateTimePicker.axaml	Adds .Small/.Large selectors to override MinHeight for DateTimePicker.
src/Ursa.Themes.Semi/Controls/DateRangePicker.axaml	Adds .Small/.Large selectors to override MinHeight for DateRangePicker.
src/Ursa.Themes.Semi/Controls/TimeRangePicker.axaml	Adds .Small/.Large selectors to override MinHeight for TimeRangePicker.

[github-actions]

Test Results

715 tests  ±0   715 ✅ ±0   18s ⏱️ +3s
  2 suites ±0     0 💤 ±0 
  2 files   ±0     0 ❌ ±0 

Results for commit 648e8ab. ± Comparison against base commit 13362d6.

♻️ This comment has been updated with latest results.

[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
Ursa	41%	31%	9045	✔
Ursa.Themes.Semi	61%	68%	1021	✔
Summary	49% (10700 / 21997)	34% (2640 / 7741)	10066	✔