[Docs] Add <LangLink> component and fix a few links

teams.md/docs/main/teams/app-authentication/README.md → teams.md/docs/main/teams/app-authentication/README.mdx

@@ -3,6 +3,8 @@ sidebar_position: 4
 summary: Set up authentication for your Teams bot using client secrets, user managed identities, or federated identity credentials
 ---
 
+import LangLink from '@site/src/components/LangLink';
+
 # App Authentication Setup
 
 Your Teams bot needs to authenticate with Azure to send messages. This involves configuring your Azure Bot Service and App Registration correctly.
@@ -19,7 +21,7 @@ Each method has different setup requirements in Azure Portal or Azure CLI.
 
 ## After Setup
 
-Once you've completed the Azure setup for your chosen authentication method, you'll need to configure your application code. See the [App Authentication configuration guide](../../teams/app-authentication/) for details on environment variables and code configuration.
+Once you've completed the Azure setup for your chosen authentication method, you'll need to configure your application code. See the <LangLink to="essentials/app-authentication">App Authentication configuration guide</LangLink> for details on environment variables and code configuration.
 
 ## Troubleshooting
 

teams.md/docs/main/welcome.md → teams.md/docs/main/welcome.mdx

@@ -4,6 +4,8 @@ summary: Welcome guide to Teams SDK, covering the quickstart process and how to
 llms: ignore
 ---
 
+import LangLink from '@site/src/components/LangLink';
+
 # 👋 Welcome
 
 Teams SDK is a suite of packages used to develop on Microsoft Teams. Rebuilt from the ground up with improved developer experience in mind, it's never been easier to build powerful agents and applications for the hundreds of millions Microsoft Teams users.
@@ -32,7 +34,7 @@ npx @microsoft/teams.cli@latest new python quote-agent --template echo
 
 ## Overview
 
-Microsoft Teams has a robust developer ecosystem with a broad suite of capabilities, now unified via Teams SDK. Whether you are building [AI-powered agents](/typescript/in-depth-guides/ai), [message extensions](/typescript/in-depth-guides/message-extensions), embedded web applications, or Graph, Teams SDK has you covered.
+Microsoft Teams has a robust developer ecosystem with a broad suite of capabilities, now unified via Teams SDK. Whether you are building <LangLink to="in-depth-guides/ai">AI-powered agents</LangLink>, <LangLink to="in-depth-guides/message-extensions">message extensions</LangLink>, embedded web applications, or Graph, Teams SDK has you covered.
 
 ## ⭐ What's new?
 

teams.md/src/components/LangLink.tsx

@@ -0,0 +1,20 @@
+import React, { type PropsWithChildren } from 'react';
+import Link from '@docusaurus/Link';
+import { useLanguagePreference } from '../hooks/useLanguagePreference';
+
+interface LangLinkProps {
+  /** Path relative to the language root, e.g. "essentials/app-authentication" */
+  to: string;
+}
+
+/**
+ * A link component that automatically prefixes the path with the user's
+ * selected language preference.
+ *
+ * Usage: <LangLink to="essentials/app-authentication">Link text</LangLink>
+ * Renders: <a href="/typescript/essentials/app-authentication">Link text</a>
+ */
+export default function LangLink({ to, children }: PropsWithChildren<LangLinkProps>) {
+  const { language } = useLanguagePreference();
+  return <Link to={`/${language}/${to}`}>{children}</Link>;
+}

teams.md/src/pages/templates/essentials/app-authentication.mdx

@@ -2,7 +2,7 @@
 sidebar_position: 5
 title: App Authentication
 summary: Configure app authentication in your Teams SDK application using client secrets, user managed identities, or federated identity credentials
-languages: ['typescript','python']
+languages: ['typescript','python','csharp']
 ---
 
 # App Authentication

teams.md/static/missing-pages.json

@@ -1,7 +1,4 @@
 {
-  "essentials/app-authentication": [
-    "csharp"
-  ],
   "essentials/on-activity/activity-ref": [
     "csharp",
     "python"