fix: Add missing vscode mock method and execa mock for McpHub tests

- Added createTextEditorDecorationType to vscode mock in McpHub.test.ts
- Created execa mock to handle ESM module import issues
- Fixes test failure that was exposed by PR #4267's module loading changes

Author: daniel-lxs

src/__mocks__/execa.js

@@ -0,0 +1,29 @@
+const execa = jest.fn().mockResolvedValue({
+	stdout: "",
+	stderr: "",
+	exitCode: 0,
+	failed: false,
+	killed: false,
+	signal: null,
+	timedOut: false,
+})
+
+class ExecaError extends Error {
+	constructor(message) {
+		super(message)
+		this.name = "ExecaError"
+		this.exitCode = 1
+		this.stdout = ""
+		this.stderr = message
+		this.failed = true
+		this.timedOut = false
+		this.isCanceled = false
+		this.killed = false
+		this.signal = null
+	}
+}
+
+module.exports = {
+	execa,
+	ExecaError,
+}

src/services/mcp/__tests__/McpHub.test.ts

@@ -22,6 +22,9 @@ jest.mock("vscode", () => ({
 		showErrorMessage: jest.fn(),
 		showInformationMessage: jest.fn(),
 		showWarningMessage: jest.fn(),
+		createTextEditorDecorationType: jest.fn().mockReturnValue({
+			dispose: jest.fn(),
+		}),
 	},
 	Disposable: {
 		from: jest.fn(),