Mise à jour du thème et améliorations de la mise en page

Supprime les partiels surchargés (nav, SEO structuré) au profit du thème
amont, réécrit header.html sans Scratch pour la compatibilité Hugo moderne,
adapte footer et CSS au Bootstrap 5 (offset-*, list-inline-item, dropdown).

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

layouts/partials/seo/structured/article.html

@@ -1,28 +0,0 @@
-<script type="application/ld+json">
-{
-  "@context": "http://schema.org",
-  "@type": "Article",
-  "author": {
-    "name" : "{{ if .Params.author -}}{{ .Params.author }}{{- else if .Site.Params.author.name -}}{{ .Site.Params.author.name }}{{- end }}"
-  },
-  "headline": "{{ .Title }}",
-  "description" : "{{ if .Description }}{{ .Description | plainify }}{{ else }}{{if .IsPage}}{{ .Summary | plainify  }}{{ end }}{{ end }}",
-  "inLanguage" : "{{ .Lang }}",
-  "wordCount": {{ .WordCount }},
-  "datePublished" : "{{ .PublishDate.Format "2006-01-02T15:04:05-07:00" }}",
-  "dateModified" : "{{ .Lastmod.Format "2006-01-02T15:04:05-07:00"  }}",
-  "image" : "{{ .Params.share_img | default .Params.image | default .Site.Params.logo | absURL }}",
-  "keywords" : [ "{{ range $i, $e := .Params.tags }}{{ if $i }}, {{ end }}{{ $e }}{{ end }}" ],
-  "mainEntityOfPage" : "{{ .Permalink }}",
-  "publisher" : {
-    "@type": "Organization",
-    "name" : "{{ .Site.BaseURL }}",
-    "logo" : {
-        "@type" : "ImageObject",
-        "url" : "{{ .Site.Params.logo | absURL }}",
-        "height" :  60 ,
-        "width" :  60
-    }
-  }
-}
-</script>

layouts/partials/seo/structured/breadcrumb.html

@@ -1,21 +0,0 @@
-<script type="application/ld+json">
-{
-  "@context": "http://schema.org",
-  "@type": "BreadcrumbList",
-  "itemListElement": [{
-        "@type": "ListItem",
-        "position": 1,
-        "item": {
-          "@id": "{{ .Site.BaseURL }}",
-          "name": "home"
-        }
-    },{
-        "@type": "ListItem",
-        "position": 2,
-        "item": {
-          "@id": "{{ .Permalink }}",
-          "name": "{{ .Title | humanize }}"
-        }
-    }]
-}
-</script>