fix: align site scaffold with calepin conventions

Assisted-by: Delta:zai-glm-5.3

site/404.typ

@@ -1,5 +1,5 @@
-#import "@preview/calepin:0.1.7": *
+#set document(title: [Not found])
 
-= 404
+#title()
 
-Page not found.
+The requested page does not exist.

site/calepin.toml

@@ -1,7 +1,7 @@
 title = "Yggdrasil"
-description = "Knowledge Base"
+description = "Personal knowledge base."
+base-url = "https://yggdrasil.kb28.ch"
 theme = "calepin"
-
 pdf = false
 
 [static]
@@ -12,14 +12,24 @@ fold = false
 
 [[sidebar.section]]
 title = "Start"
+
   [[sidebar.section.item]]
   target = "index.typ"
 
 [[sidebar.section]]
-title = "Categories"
+title = "Thermodynamics"
+
   [[sidebar.section.item]]
   target = "thermo/index.typ"
+
+[[sidebar.section]]
+title = "Security"
+
   [[sidebar.section.item]]
   target = "security/index.typ"
+
+[[sidebar.section]]
+title = "Homelab"
+
   [[sidebar.section.item]]
   target = "homelab/index.typ"

site/homelab/index.typ

@@ -1,3 +1,7 @@
-#import "@preview/calepin:0.1.7": *
+#set document(title: [Homelab])
+#metadata((title: "Overview", translation_key: "homelab")) <website-metadata>
 
-= Homelab
+#title()
+
+Placeholder page for the homelab category.
+The real content comes later.

site/index.typ

@@ -1,5 +1,11 @@
-#import "@preview/calepin:0.1.7": *
+#set document(title: [Yggdrasil])
+#metadata((title: "Home", translation_key: "home")) <website-metadata>
 
-= Yggdrasil
+#title()
 
-Welcome to Yggdrasil, the central knowledge base.
+Welcome to Yggdrasil, my personal knowledge base.
+Pick a category from the sidebar to start reading:
+
+- Thermodynamics — heat, energy, and friends
+- Security — hardening, cryptography, and operations
+- Homelab — self-hosted services and infrastructure

site/security/index.typ

@@ -1,3 +1,7 @@
-#import "@preview/calepin:0.1.7": *
+#set document(title: [Security])
+#metadata((title: "Overview", translation_key: "security")) <website-metadata>
 
-= Security
+#title()
+
+Placeholder page for the security category.
+The real content comes later.

site/thermo/index.typ

@@ -1,3 +1,7 @@
-#import "@preview/calepin:0.1.7": *
+#set document(title: [Thermodynamics])
+#metadata((title: "Overview", translation_key: "thermo")) <website-metadata>
 
-= Thermodynamics
+#title()
+
+Placeholder page for the thermodynamics category.
+The real content comes later.