build: bump Hugo to 0.162.1 and fix deferred CSS template

Hugo 0.162 disallows templates.Defer inside a partialCached partial.
The CSS partial uses templates.Defer with a global key, so switch its
caller in head.html from partialCached to partial (the global Defer key
already dedupes the work). Bump the pinned Hugo version in the Dockerfile
and netlify.toml.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -5,7 +5,7 @@ ARG ALPINE_VERSION=3.23
 ARG GO_VERSION=1.26
 ARG HTMLTEST_VERSION=0.17.0
 ARG VALE_VERSION=3.11.2
-ARG HUGO_VERSION=0.161.1
+ARG HUGO_VERSION=0.162.1
 ARG NODE_VERSION=24
 ARG PAGEFIND_VERSION=1.5.2
 

layouts/_partials/head.html

@@ -16,7 +16,7 @@
     />
   {{- end -}}
 {{ end -}}
-{{ partialCached "utils/css.html" "-" "-" }}
+{{ partial "utils/css.html" . }}
 <link href="/pagefind/pagefind-component-ui.css" rel="stylesheet" />
 {{- if hugo.IsProduction -}}
   <script

netlify.toml

@@ -4,7 +4,7 @@ publish = "public"
 [context.deploy-preview.environment]
 NODE_VERSION = "24"
 NODE_ENV = "production"
-HUGO_VERSION = "0.161.1"
+HUGO_VERSION = "0.162.1"
 HUGO_ENABLEGITINFO = "true"
 HUGO_ENVIRONMENT = "preview"
 SECRETS_SCAN_OMIT_PATHS = "public/contribute/file-conventions/index.html"