add tracing project custom rendering docs (#1763)

## Overview

Added instructions for configuring custom output rendering at the
tracing project level in `custom-output-rendering.mdx`. This update
includes steps for enabling custom rendering within tracing project
settings and updates the precedence rules to include tracing projects.

## Type of change

**Type:** Update existing documentation

## Related issues/PRs

<!-- Link to related issues, feature PRs, or discussions (if applicable)
-->

- GitHub issue:

- Feature PR: langchain-ai/langchainplus#14495

## Checklist

<!-- Put an 'x' in all boxes that apply -->
- [x] I have read the [contributing guidelines](README.md)
- [x] I have tested my changes locally using `docs dev`
- [x] All code examples have been tested and work correctly
- [x] I have used **root relative** paths for internal links
- [x] I have updated navigation in `src/docs.json` if needed

## Additional notes

The precedence for custom rendering settings is now: annotation queue >
dataset > tracing project.

Co-authored-by: Mason Daugherty <mason@langchain.dev>

Author: eric-langchain

src/langsmith/custom-output-rendering.mdx

@@ -5,21 +5,34 @@ sidebarTitle: Custom output rendering
 
 Custom output rendering allows you to visualize run outputs and dataset reference outputs using your own custom HTML pages. This is particularly useful for:
 
-- **Domain-specific formatting**: Display medical records, legal documents, or other specialized data types in their native format.
-- **Custom visualizations**: Create charts, graphs, or diagrams from numeric or structured output data.
+-   **Domain-specific formatting**: Display medical records, legal documents, or other specialized data types in their native format.
+-   **Custom visualizations**: Create charts, graphs, or diagrams from numeric or structured output data.
 
 In this page you'll learn how to:
 
-- **[Configure custom rendering](#configure-custom-output-rendering)** in the LangSmith UI.
-- **[Build a custom renderer](#build-a-custom-renderer)** to display output data.
-- **[Understand where custom rendering appears](#where-custom-rendering-appears)** in LangSmith.
+-   **[Configure custom rendering](#configure-custom-output-rendering)** in the LangSmith UI.
+-   **[Build a custom renderer](#build-a-custom-renderer)** to display output data.
+-   **[Understand where custom rendering appears](#where-custom-rendering-appears)** in LangSmith.
 
 ## Configure custom output rendering
 
 Configure custom rendering at two levels:
 
-- **For datasets**: Apply custom rendering to all runs associated with that dataset, wherever they appear—in experiments, run detail panes, or annotation queues.
-- **For annotation queues**: Apply custom rendering to all runs within a specific annotation queue, regardless of which dataset they come from. This takes precedence over dataset-level configuration.
+-   **For datasets**: Apply custom rendering to all runs associated with that dataset, wherever they appear—in experiments, run detail panes, or annotation queues.
+-   **For annotation queues**: Apply custom rendering to all runs within a specific annotation queue, regardless of which dataset they come from. This takes precedence over dataset-level configuration.
+
+### For tracing projects
+
+To configure custom output rendering for a tracing project:
+
+![Tracing project settings showing custom output rendering configuration](/langsmith/images/tracing-project-custom-output-rendering-settings.png)
+
+1. Navigate to the **Tracing Projects** page.
+2. Click on an existing tracing project or create a new one.
+3. In the edit tracing project pane, scroll to the **Custom Output Rendering** section.
+4. Toggle **Enable custom output rendering**.
+5. Enter the webpage URL in the **URL** field.
+6. Click **Save**.
 
 ### For datasets
 
@@ -49,9 +62,7 @@ To configure custom output rendering for an annotation queue:
 5. Enter the webpage URL in the **URL** field.
 6. Click **Save** or **Create**.
 
-<Info>
-When custom rendering is configured at both levels, annotation queue configuration takes precedence over dataset configuration for runs viewed within that queue.
-</Info>
+<Info>When custom rendering settings are applied at multiple levels, the precedence is as follows: annotation queue > dataset > tracing project.</Info>
 
 ## Build a custom renderer
 
@@ -75,13 +86,11 @@ Your HTML page will receive output data via the [postMessage API](https://develo
 }
 ```
 
-- `type`: Indicates whether this is an actual output (`"output"`) or a reference output (`"reference"`).
-- `data`: The output data itself.
-- `metadata.inputs`: The input data that generated this output, provided for context.
+-   `type`: Indicates whether this is an actual output (`"output"`) or a reference output (`"reference"`).
+-   `data`: The output data itself.
+-   `metadata.inputs`: The input data that generated this output, provided for context.
 
-<Note>
-**Message delivery timing**: LangSmith uses an exponential backoff retry mechanism to ensure your page receives the data even if it loads slowly. Messages are sent up to 6 times with increasing delays (100ms, 200ms, 400ms, 800ms, 1600ms, 3200ms).
-</Note>
+<Note>**Message delivery timing**: LangSmith uses an exponential backoff retry mechanism to ensure your page receives the data even if it loads slowly. Messages are sent up to 6 times with increasing delays (100ms, 200ms, 400ms, 800ms, 1600ms, 3200ms).</Note>
 
 ### Example implementation
 
@@ -90,46 +99,44 @@ This example listens for incoming postMessage events and displays them on the pa
 ```html
 <!DOCTYPE html>
 <html>
-  <head>
-    <meta charset="UTF-8" />
-    <title>PostMessage Echo</title>
-    <link rel="stylesheet" href="https://unpkg.com/sakura.css/css/sakura.css" />
-  </head>
-  <body>
-    <h1>PostMessage Messages</h1>
-    <div id="messages"></div>
-    <script>
-      let count = 0;
-      window.addEventListener("message", (event) => {
-        count++;
-        const header = document.createElement("h3");
-        header.appendChild(document.createTextNode(`Message ${count}`));
-        const code = document.createElement("code");
-        code.appendChild(
-          document.createTextNode(JSON.stringify(event.data, null, 2))
-        );
-        const pre = document.createElement("pre");
-        pre.appendChild(code);
-        document.getElementById("messages").appendChild(header);
-        document.getElementById("messages").appendChild(pre);
-      });
-    </script>
-  </body>
+    <head>
+        <meta charset="UTF-8" />
+        <title>PostMessage Echo</title>
+        <link rel="stylesheet" href="https://unpkg.com/sakura.css/css/sakura.css" />
+    </head>
+    <body>
+        <h1>PostMessage Messages</h1>
+        <div id="messages"></div>
+        <script>
+            let count = 0;
+            window.addEventListener("message", (event) => {
+                count++;
+                const header = document.createElement("h3");
+                header.appendChild(document.createTextNode(`Message ${count}`));
+                const code = document.createElement("code");
+                code.appendChild(document.createTextNode(JSON.stringify(event.data, null, 2)));
+                const pre = document.createElement("pre");
+                pre.appendChild(code);
+                document.getElementById("messages").appendChild(header);
+                document.getElementById("messages").appendChild(pre);
+            });
+        </script>
+    </body>
 </html>
 ```
 
 ## Where custom rendering appears
 
 When enabled, your custom rendering will replace the default output view in:
 
-- **Experiment comparison view**: When comparing outputs across multiple experiments:
+-   **Experiment comparison view**: When comparing outputs across multiple experiments:
 
 ![Experiment comparison view showing custom rendering](/langsmith/images/custom-output-rendering-experiment-comparison.png)
 
-- **Run detail panes**: When viewing runs that are associated with a dataset:
+-   **Run detail panes**: When viewing runs that are associated with a dataset:
 
 ![Run detail pane showing custom rendering](/langsmith/images/custom-output-rendering-run-details.png)
 
-- **Annotation queues**: When reviewing runs in annotation queues:
+-   **Annotation queues**: When reviewing runs in annotation queues:
 
 ![Annotation queue showing custom rendering](/langsmith/images/custom-output-rendering-annotation-queue.png)