feat: implement fuzzy search and replace functionality with Levenshtein distance

- Added `applySearchReplace` function to handle search and replace operations with fuzzy matching capabilities.
- Introduced tests for various scenarios including fuzzy matching with typos, exact matches, and handling whitespace differences.
- Created a parser for search/replace blocks to facilitate the new functionality.
- Updated prompts for search-replace operations to clarify usage and examples.
- Added utility functions for text normalization and language detection based on file extensions.
- Implemented a minimal stdio MCP server for local testing with tools for adding numbers and printing environment variables.

e2e-tests/toggle_screen_sizes.spec.ts

@@ -0,0 +1,79 @@
+import { test, testSkipIfWindows, Timeout } from "./helpers/test_helper";
+import { expect } from "@playwright/test";
+
+test.describe("Toggle Screen Size Tests", () => {
+  async function setupApp(po: any) {
+    await po.setUp({ autoApprove: true });
+    await po.sendPrompt("tc=write-index");
+
+    const iframe = po.getPreviewIframeElement();
+    const frame = await iframe.contentFrame();
+
+    await expect(frame.getByText("Testing:write-index!")).toBeVisible({
+      timeout: Timeout.EXTRA_LONG,
+    });
+  }
+
+  testSkipIfWindows(
+    "should open and close device mode popover",
+    async ({ po }) => {
+      test.setTimeout(Timeout.EXTRA_LONG * 1.5);
+      await setupApp(po);
+
+      // Click the device mode button to open popover
+      const deviceModeButton = po.page.locator(
+        '[data-testid="device-mode-button"]',
+      );
+      await deviceModeButton.click();
+
+      // Verify popover is visible with device options
+      const originalButton = po.page.locator('[aria-label="Desktop view"]');
+      await expect(originalButton).toBeVisible();
+
+      // Close popover by clicking the button again
+      await deviceModeButton.click();
+
+      // Verify popover is closed
+      await expect(originalButton).toBeHidden();
+    },
+  );
+
+  testSkipIfWindows("should switch between device modes", async ({ po }) => {
+    test.setTimeout(Timeout.EXTRA_LONG * 1.5);
+    await setupApp(po);
+
+    const deviceModeButton = po.page.locator(
+      '[data-testid="device-mode-button"]',
+    );
+
+    const previewIframe = po.page.locator(
+      '[data-testid="preview-iframe-element"]',
+    );
+
+    // Switch to tablet mode
+    await deviceModeButton.click();
+    await po.page.locator('[aria-label="Tablet view"]').click();
+
+    // Wait for the iframe width to change to tablet size (768px)
+    await expect(previewIframe).toHaveAttribute("style", /width:\s*768px/);
+
+    // Verify iframe has tablet dimensions
+    const tabletWidth = await previewIframe.evaluate((el: HTMLIFrameElement) =>
+      el.style.width.replace("px", ""),
+    );
+    expect(tabletWidth).toBe("768");
+
+    // Switch to mobile mode
+    await deviceModeButton.click();
+    await po.page.locator('[aria-label="Mobile view"]').click();
+
+    // Wait for the iframe width to change to mobile size (375px)
+    await expect(previewIframe).toHaveAttribute("style", /width:\s*375px/);
+
+    // Verify iframe has mobile dimensions
+    const mobileWidth = await previewIframe.evaluate((el: HTMLIFrameElement) =>
+      el.style.width.replace("px", ""),
+    );
+    expect(mobileWidth).toBe("375");
+  });
+});