fix: change CodeActionKind from Source to RefactorExtract to auto-show lightbulb on selection

src/codeActionProvider.ts

@@ -2,7 +2,7 @@ import * as vscode from 'vscode';
 
 export class CopyAiCodeActionProvider implements vscode.CodeActionProvider {
   public static readonly providedCodeActionKinds = [
-    vscode.CodeActionKind.Source,
+    vscode.CodeActionKind.RefactorExtract,
   ];
 
   provideCodeActions(
@@ -14,7 +14,7 @@ export class CopyAiCodeActionProvider implements vscode.CodeActionProvider {
 
     const action = new vscode.CodeAction(
       '$(clippy) Copy to AI: 选中区域',
-      vscode.CodeActionKind.Source,
+      vscode.CodeActionKind.RefactorExtract,
     );
     action.command = {
       command: 'copy-ai-ctx.copySelection',