Improve various aspects of the Chat Window

[thedemons]

• The SetChatThemeAsync function was previously unreliable, occasionally failing to apply the theme. To improve reliability, the function now uses AddScriptToExecuteOnDocumentCreatedAsync to add the set-theme script to a list of scripts that are executed upon document load.
• During the chat page loading process, a 10-second timeout has been added to verify if the page has loaded. If not, the user is notified and asked whether they wish to reload the chat.
• As the webview2 operates as a separate HWND, clicking on it does not activate the ToolWindowPane (indicated by a purple strip on the title). This issue has been addressed by manually activating it during the GotFocus event. Additionally, the text input is now automatically focused for user convenience.

Also fixed a bug made in #25