添加底栏按钮，支持通过底栏按钮触发字符串转换；更新 README.md；release version 1.0.6

src/extension-handler/status-bar-handler.ts

@@ -0,0 +1,32 @@
+import * as vscode from 'vscode';
+
+// docs: https://code.visualstudio.com/api/references/vscode-api#StatusBarItem
+
+let statusBar: vscode.StatusBarItem;
+
+/**
+ * @since 2024-04-07
+ */
+export function createStatusBarItem() {
+    statusBar = vscode.window.createStatusBarItem(vscode.StatusBarAlignment.Left);
+    statusBar.text = '$(find-replace)字符串转换';
+    statusBar.command = 'variable-conversion.convertCase';
+    // statusBar.color = 'red';
+    // statusBar.show();
+}
+
+/**
+ * @since 2024-04-07
+ */
+export function updateStatusBarItemVisable(selectTextLength: number) {
+    if (!statusBar) {
+        return;
+    }
+
+    let editor = vscode.window.activeTextEditor;
+    if (editor && selectTextLength > 0) {
+        statusBar.show();
+        return;
+    }
+    statusBar.hide();
+}