Explicitly define all navbar components including home

pkgdown was adding a default Articles dropdown because the custom
component names weren't fully overriding built-in defaults. Define
all components explicitly (home, reference, intro, rnaseq, ml).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: frenkiboy

_pkgdown.yml

@@ -2,7 +2,6 @@ template:
   bootstrap: 5
   bslib:
     base_font_size: 0.9rem
-    font_size_base: 0.9
     code-font-size: 0.85rem
 
 url: https://BIMSBbioinfo.github.io/cacheR
@@ -16,6 +15,9 @@ navbar:
     left:  [home, reference, intro, rnaseq, ml]
     right: [github]
   components:
+    home:
+      text: Home
+      href: index.html
     reference:
       text: Reference
       href: reference/index.html