feat: add SEO descriptions to all pages and fix canonical URL

content/2.general/1.networking/1.nat.md

@@ -1,6 +1,7 @@
 ---
 navigation: true
 title: NAT & DHCP
+description: Learn how NAT, port forwarding, and DHCP work on a home router. Configure fixed IP leases and understand how to expose local services.
 main:
   fluid: false
 ---

content/2.general/1.networking/2.dns.md

@@ -1,6 +1,7 @@
 ---
 navigation: true
 title: DNS Zone
+description: Understand how DNS works, how to read and edit a DNS zone, and how to configure domain names for your self-hosted services.
 main:
   fluid: false
 ---

content/2.general/1.networking/3.samba.md

@@ -1,6 +1,7 @@
 ---
 navigation: true
 title: Samba
+description: Set up Samba on Debian to share folders over your local network and access them from Windows, macOS, or Linux.
 main:
   fluid: false
 ---