docs(js): Add elementTimingIntegration documentation

docs/platforms/javascript/common/configuration/integrations/elementtiming.mdx

@@ -0,0 +1,101 @@
+---
+title: ElementTiming
+description: "Collect Element Timing API data as Sentry metrics."
+beta: true
+notSupported:
+  - javascript.cordova
+  - javascript.capacitor
+  - javascript.node
+  - javascript.aws-lambda
+  - javascript.azure-functions
+  - javascript.connect
+  - javascript.express
+  - javascript.fastify
+  - javascript.gcp-functions
+  - javascript.hapi
+  - javascript.hono
+  - javascript.koa
+  - javascript.nestjs
+  - javascript.deno
+  - javascript.cloudflare
+  - javascript.bun
+---
+
+<Alert>
+
+This integration only works inside a browser environment. Requires SDK version `10.47.0` or higher.
+
+</Alert>
+
+_Import name: `Sentry.elementTimingIntegration`_
+
+The `elementTimingIntegration` collects render and load timing data from the browser's [Element Timing API](https://developer.mozilla.org/en-US/docs/Web/API/PerformanceElementTiming) and emits it as [Sentry distribution metrics](/product/explore/metrics/). This lets you track how long key elements (hero images, text blocks, etc.) take to appear on screen.
+
+<Alert>
+
+The Element Timing API is only supported in Chromium-based browsers (Chrome, Edge 77+). Firefox and Safari do not support it. The integration will silently do nothing in unsupported browsers.
+
+</Alert>
+
+This integration requires <PlatformLink to="/metrics">Sentry Metrics</PlatformLink> to be available in your Sentry organization.
+
+```javascript
+Sentry.init({
+  integrations: [Sentry.elementTimingIntegration()],
+});
+```
+
+## Marking Elements for Tracking
+
+Add the `elementtiming` HTML attribute to any element you want to track. The attribute value is used as the element's identifier in the emitted metrics.
+
+```html
+<img src="hero.jpg" elementtiming="hero-image" />
+<p elementtiming="hero-text">Welcome to our site!</p>
+```
+
+Only elements with a non-empty `elementtiming` attribute will be tracked.
+
+## Emitted Metrics
+
+The integration emits two distribution metrics (in milliseconds):
+
+| Metric                   | Description                                                                    |
+| ------------------------ | ------------------------------------------------------------------------------ |
+| `ui.element.render_time` | Time until the element was rendered. Emitted for both text and image elements. |
+| `ui.element.load_time`   | Time until the element's resource was loaded. Only emitted for image elements. |
+
+Both metrics include the following attributes:
+
+| Attribute               | Description                                      |
+| ----------------------- | ------------------------------------------------ |
+| `ui.element.identifier` | The value of the `elementtiming` HTML attribute. |
+| `ui.element.paint_type` | The type of paint event: `image-paint` or `text-paint`. |
+| `ui.element.id`         | The DOM element's `id` attribute, if set.        |
+| `ui.element.type`       | The tag name (e.g., `img`, `p`).                 |
+| `ui.element.url`        | The image resource URL, if available.            |
+| `ui.element.width`      | Natural width of the image, if available.        |
+| `ui.element.height`     | Natural height of the image, if available.       |
+
+## Migration from `enableElementTiming`
+
+The `enableElementTiming` option on `browserTracingIntegration` is deprecated and no longer has any effect. If you were using it, remove it and add the standalone `elementTimingIntegration` instead:
+
+```javascript
+// Before
+Sentry.init({
+  integrations: [
+    Sentry.browserTracingIntegration({
+      enableElementTiming: true, // deprecated, no longer works
+    }),
+  ],
+});
+
+// After
+Sentry.init({
+  integrations: [
+    Sentry.browserTracingIntegration(),
+    Sentry.elementTimingIntegration(),
+  ],
+});
+```

docs/platforms/javascript/common/metrics/index.mdx

@@ -39,6 +39,14 @@ With [Sentry Metrics](/product/explore/metrics/), you can send counters, gauges,
 
 <PlatformContent includePath="metrics/default-attributes" />
 
+## Integrations
+
+<PlatformSection notSupported={["javascript.node", "javascript.aws-lambda", "javascript.azure-functions", "javascript.connect", "javascript.express", "javascript.fastify", "javascript.gcp-functions", "javascript.hapi", "javascript.hono", "javascript.koa", "javascript.nestjs", "javascript.deno", "javascript.cloudflare", "javascript.bun"]}>
+
+- <PlatformLink to="/configuration/integrations/elementtiming/">`elementTimingIntegration`</PlatformLink> — Automatically collect render and load timing distribution metrics for key UI elements using the browser's Element Timing API.
+
+</PlatformSection>
+
 ## Related Features
 
 - <PlatformLink to="/tracing/">Tracing</PlatformLink> — Drill down from metrics

platform-includes/configuration/integrations/javascript.mdx

@@ -1,7 +1,7 @@
 ### Integrations
 
 |                                                       | **Auto Enabled** | **Errors** | **Tracing** | **Replay** | **Additional Context** |
-|-------------------------------------------------------|:----------------:|:----------:|:-----------:|:----------:|:----------------------:|
+| ----------------------------------------------------- | :--------------: | :--------: | :---------: | :--------: | :--------------------: |
 | [`breadcrumbsIntegration`](./breadcrumbs)             |        ✓         |            |             |            |           ✓            |
 | [`browserApiErrorsIntegration`](./browserapierrors)   |        ✓         |     ✓      |             |            |                        |
 | [`browserSessionIntegration`](./browsersession)       |        ✓         |            |             |            |           ✓            |
@@ -14,6 +14,7 @@
 | [`anthropicAIIntegration`](./anthropic)               |                  |            |      ✓      |            |           ✓            |
 | [`browserProfilingIntegration`](./browserprofiling)   |                  |            |      ✓      |            |                        |
 | [`browserTracingIntegration`](./browsertracing)       |                  |            |      ✓      |            |           ✓            |
+| [`elementTimingIntegration`](./elementtiming)         |                  |            |             |            |                        |
 | [`captureConsoleIntegration`](./captureconsole)       |                  |     ✓      |             |            |           ✓            |
 | [`contextLinesIntegration`](./contextlines)           |                  |     ✓      |             |            |                        |
 | [`extraErrorDataIntegration`](./extraerrordata)       |                  |            |             |            |           ✓            |