Fix duplicate panel title and clipped toolbar buttons

[DaveTseng2019]

Summary

• Removed the redundant "Claude Code" text in the panel body — the tool window's own Caption already shows it in the tab.
• Changed the Launch Claude Code / External console toolbar from a fixed-layout DockPanel+StackPanel to a WrapPanel, so the buttons wrap to a new line instead of getting clipped when the panel is docked narrower than they fit (matches the pattern already used for the checkbox row below).

Test plan

• MSBuild.exe ClaudeCodeVS.csproj /t:Build /p:Configuration=Release — clean build (only pre-existing nullable warnings)
• Verified visually in the experimental instance: floated the panel at 600px (buttons on one row, no duplicate title) and 300px (buttons wrap onto multiple lines, none clipped)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR improves the Visual Studio tool window UI by removing a duplicated “Claude Code” title inside the panel content (since the tool window tab caption already provides it) and by making the toolbar buttons wrap instead of being clipped in narrow docked layouts.

Changes:

• Removed the redundant “Claude Code” TextBlock from the panel header, leaving the status pill + endpoint line.
• Replaced the fixed-layout DockPanel/StackPanel toolbar with a single WrapPanel so all four buttons remain accessible at narrow widths.

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[DaveTseng2019]

這個 PR 的內容已經被 #24 取代（同一個分支，追加了右鍵選單功能並修完 Copilot review 意見），麻煩直接看 #24，這邊可以維持 closed。