fix: add environment overrides to sidebar and beta warning (#166)

Co-authored-by: shane <shane@swalker.dev>

Author: ryok90

docs/features/environment-overrides.mdx

@@ -7,6 +7,10 @@ description: Dynamically control remote dependencies and environment variables p
 
 One of Zephyr's most powerful capabilities is the ability to override application configuration on a per-deployment-environment basis. This means the same built application can dynamically adapt its behavior - consuming different versions of remote dependencies and using different environment variable values - depending on which environment URL serves it.
 
+:::warning Environment-Level Overrides Beta
+The features described on this page are currently in Beta, which means we are still improving and polishing every step of the implementation.
+:::
+
 ## Overview
 
 Environment-level overrides enable two key capabilities:

rspress.config.ts

@@ -81,6 +81,10 @@ const sidebar: Sidebar = {
           text: 'Remote Dependencies',
           link: '/features/remote-dependencies',
         },
+        {
+          text: 'Environment Overrides',
+          link: '/features/environment-overrides',
+        },
         {
           text: 'CI/CD',
           link: '/features/ci-cd',