Basic unit testing for frontend /webview-ui (RooCodeInc#1522)

* feat: very basic unit testing

* move dep -> devDeps

* correct other deps

* resync after i18n revert on main

* update package-lock.json

Author: brownrw8

webview-ui/matchMedia.js

@@ -0,0 +1,16 @@
+// "Official" jest workaround for mocking window.matchMedia()
+// https://jestjs.io/docs/manual-mocks#mocking-methods-which-are-not-implemented-in-jsdom
+
+Object.defineProperty(window, "matchMedia", {
+	writable: true,
+	value: vi.fn().mockImplementation((query) => ({
+		matches: false,
+		media: query,
+		onchange: null,
+		addListener: vi.fn(), // Deprecated
+		removeListener: vi.fn(), // Deprecated
+		addEventListener: vi.fn(),
+		removeEventListener: vi.fn(),
+		dispatchEvent: vi.fn(),
+	})),
+})