Only create mods and temp directories when needed

[ManlyMarco]

No description provided.

[Copilot]

Pull Request Overview

This PR optimizes directory creation by deferring the creation of the mods and temp directories until they are actually needed, rather than creating them during initialization. The property ModsPath has been renamed to ZipmodsPath to better reflect its purpose of storing zipmod files.

Key changes:

• Renamed ModsPath to ZipmodsPath throughout the codebase for clarity
• Changed directory initialization from Directory.CreateDirectory() to new DirectoryInfo() for mods and temp directories to avoid creating them unnecessarily
• Added existence checks before accessing these directories to prevent errors when they don't exist yet

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/KKManager.Core/Functions/InstallDirectoryHelper.cs	Renamed ModsPath to ZipmodsPath and changed initialization to use DirectoryInfo constructor instead of creating directories
src/KKManager.Core/Data/Zipmods/SideloaderModLoader.cs	Updated reference from ModsPath to ZipmodsPath
src/KKManager.Core/Functions/ModInstaller.cs	Updated reference from ModsPath to ZipmodsPath
src/KKManager.Updater/Windows/ModUpdateProgressDialog.cs	Added existence checks before accessing PluginPath and ZipmodsPath directories
src/KKManager/Windows/MainWindow.cs	Updated reference from ModsPath to ZipmodsPath

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