docs: add coverage utils

packages/blade/docs/utils/coverge.stories.mdx

@@ -0,0 +1,42 @@
+import { Meta } from '@storybook/addon-docs';
+
+<Meta title="Utils/coverage" />
+
+## `getBladeCoverage`
+
+This utility function calculates the blade usage coverage in percentage of the DOM elements on a web page.
+
+
+```js dark
+import { getBladeCoverage } from '@razorpay/blade/coverage';
+
+const { bladeCoverage, totalNodes, bladeNodes } = getBladeCoverage();
+```
+
+- `bladeCoverage`: The percentage of blade nodes in the total nodes.
+- `totalNodes`: Total number of DOM nodes.
+- `bladeNodes`: Number of blade nodes.
+
+## `assertBladeCoverage`
+
+This utility function asserts that the calculated blade coverage meets a specified threshold.
+
+Parameters:
+- `page`: Playwright page object.
+- `expect`: @playwright/test expect function.
+- `threshold` (optional): Minimum threshold for blade coverage (default is 70).
+
+### Example
+
+```js dark
+import { test, expect } from '@playwright/test';
+import { assertBladeCoverage } from '@razorpay/blade/coverage';
+
+test.describe.parallel('Test Home @flow=home', () => {
+  test('should have blade coverage more than 70% @priority=normal', async ({ page }) => {
+    await page.goto('/');
+
+    await assertBladeCoverage({ page, expect, threshold: 70 });
+  });
+});
+```