feat(messaging): introduce comprehensive setup docs for Telegram, WhatsApp, Slack, and Discord messaging channels

surfsense_web/content/docs/messaging-channels/index.mdx

@@ -0,0 +1,42 @@
+---
+title: Messaging Channels
+description: Chat with SurfSense from Telegram, WhatsApp, Slack, and Discord
+---
+
+import { Card, Cards } from 'fumadocs-ui/components/card';
+
+Choose the external chat app you want to connect to SurfSense. Each guide shows
+the required app setup, environment variables, and pairing flow.
+
+<Cards>
+  <Card
+    title="Telegram"
+    description="Enable SurfSense chat from Telegram"
+    href="/docs/messaging-channels/telegram"
+  />
+  <Card
+    title="WhatsApp"
+    description="Enable SurfSense chat from WhatsApp"
+    href="/docs/messaging-channels/whatsapp"
+  />
+  <Card
+    title="Slack"
+    description="Enable the SurfSense bot for in-Slack agent chat"
+    href="/docs/messaging-channels/slack"
+  />
+  <Card
+    title="Discord"
+    description="Enable the SurfSense bot for in-Discord agent chat"
+    href="/docs/messaging-channels/discord"
+  />
+  <Card
+    title="Docker Setup"
+    description="Configure messaging channels for Docker and one-line installs"
+    href="/docs/messaging-channels/docker"
+  />
+  <Card
+    title="Troubleshooting"
+    description="Common pairing, webhook, and bot reply issues"
+    href="/docs/messaging-channels/troubleshooting"
+  />
+</Cards>