Restrict AI context menu to Ctrl + selection + right-click

[Cinnavun]

addresses #2
Problem: On text selection, the plugin's popup menu replaces Notepad++'s default right-click context menu entirely, rather than appending to it.

Change: The AI plugin context menu now only appears when ctrlPressed + hasSelection — i.e., Ctrl + right-click with an active selection. Right-click otherwise retains the standard Notepad++ menu.

Alternative: Since the AI context commands mirror the Plugin Menu commands, users can add the following lines to contextMenu.xml (%APPDATA%\Notepad++\contextMenu.xml) to append safely and access them without holding ctrl.

		<Item FolderName="Plugin commands" TranslateID="contextMenu-PluginCommands" PluginEntryName="NppAIAssistant" PluginCommandItemName="Explain Selection" />
		<Item FolderName="Plugin commands" TranslateID="contextMenu-PluginCommands" PluginEntryName="NppAIAssistant" PluginCommandItemName="Fix Selection" />
		<Item FolderName="Plugin commands" TranslateID="contextMenu-PluginCommands" PluginEntryName="NppAIAssistant" PluginCommandItemName="Refactor Selection" />
		<Item FolderName="Plugin commands" TranslateID="contextMenu-PluginCommands" PluginEntryName="NppAIAssistant" PluginCommandItemName="Add Comments to Selection" />

Built x64 | Release and tested on Windows - confirmed all the above working