chore: adapt theme to new template system (#696)

* Adapted theme's layout to [Hugo v0.146.0](https://gohugo.io/templates/new-templatesystem-overview/)
* Bumped minimal Hugo version to v0.146.0

layouts/_partials/scripts/core.html

@@ -0,0 +1,14 @@
+{{- $jsTheme := resources.Get "js/theme.js" | resources.ExecuteAsTemplate "theme.js" . -}}
+{{- $jsMenu := resources.Get "js/menu.js" -}}
+{{- $jsTabs := resources.Get "js/tabs.js" -}}
+{{- $jsLang := resources.Get "js/lang.js" -}}
+{{- $jsCodeCopy := resources.Get "js/code-copy.js" -}}
+{{- $jsFileTree := resources.Get "js/filetree.js" -}}
+{{- $jsSidebar := resources.Get "js/sidebar.js" -}}
+{{- $jsBackToTop := resources.Get "js/back-to-top.js" -}}
+
+{{- $scripts := slice $jsTheme $jsMenu $jsCodeCopy $jsTabs $jsLang $jsFileTree $jsSidebar $jsBackToTop | resources.Concat "js/main.js" -}}
+{{- if hugo.IsProduction -}}
+  {{- $scripts = $scripts | minify | fingerprint -}}
+{{- end -}}
+<script defer src="{{ $scripts.RelPermalink }}" integrity="{{ $scripts.Data.Integrity }}"></script>

layouts/_partials/scripts/mermaid.html

@@ -0,0 +1,44 @@
+{{/* Mermaid */}}
+
+{{ $mermaidJsUrl := printf "https://cdn.jsdelivr.net/npm/mermaid@latest/dist/mermaid%s.js" (cond hugo.IsProduction ".min" "") -}}
+{{ with try (resources.GetRemote $mermaidJsUrl) -}}
+  {{ with .Err -}}
+    {{ errorf "Could not retrieve Mermaid js file from %s. Reason: %s." $mermaidJsUrl . -}}
+  {{ else with.Value -}}
+    {{ with resources.Copy (printf "js/mermaid.min.js") . -}}
+      {{ $mermaidJs := . | fingerprint -}}
+      <script defer src="{{ $mermaidJs.RelPermalink }}" integrity="{{ $mermaidJs.Data.Integrity }}" crossorigin="anonymous"></script>
+    {{ end -}}
+  {{ end -}}
+{{ end -}}
+
+
+<script>
+  document.addEventListener("DOMContentLoaded", () => {
+    // Store original mermaid code for each diagram
+    document.querySelectorAll(".mermaid").forEach((el) => {
+      el.dataset.original = el.innerHTML;
+    });
+
+    const theme = document.documentElement.classList.contains("dark") ? "dark" : "default";
+    mermaid.initialize({ startOnLoad: true, theme: theme });
+
+    let timeout;
+    new MutationObserver(() => {
+      clearTimeout(timeout);
+      timeout = setTimeout(() => {
+        const theme = document.documentElement.classList.contains("dark") ? "dark" : "default";
+        document.querySelectorAll(".mermaid").forEach((el) => {
+          // Reset to original content, preserving HTML
+          el.innerHTML = el.dataset.original;
+          el.removeAttribute("data-processed");
+        });
+        mermaid.initialize({ startOnLoad: true, theme: theme });
+        mermaid.init();
+      }, 150);
+    }).observe(document.documentElement, {
+      attributes: true,
+      attributeFilter: ["class"],
+    });
+  });
+</script>

layouts/_partials/scripts/search.html

@@ -0,0 +1,26 @@
+{{/* Search */}}
+{{- if (site.Params.search.enable | default true) -}}
+  {{- $searchType := site.Params.search.type | default "flexsearch" -}}
+  {{- if eq $searchType "flexsearch" -}}
+    {{- $jsSearchScript := printf "%s.search.js" .Language.Lang -}}
+    {{- $jsSearch := resources.Get "js/flexsearch.js" | resources.ExecuteAsTemplate $jsSearchScript . -}}
+    {{- if hugo.IsProduction -}}
+      {{- $jsSearch = $jsSearch | minify | fingerprint -}}
+    {{- end -}}
+    {{- $flexSearchVersion := site.Params.search.flexsearch.version | default "0.8.143" -}}
+    {{- $flexSearchJsUrl := printf "https://cdn.jsdelivr.net/npm/flexsearch@%s/dist/flexsearch.bundle%s.js" $flexSearchVersion (cond hugo.IsProduction ".min" ".debug") -}}
+    {{ with try (resources.GetRemote $flexSearchJsUrl) -}}
+      {{ with .Err -}}
+        {{ errorf "Could not retrieve FlexSearch js file from %s. Reason: %s." $flexSearchJsUrl . -}}
+      {{ else with.Value -}}
+        {{ with resources.Copy (printf "js/flexsearch.js") . -}}
+          {{ $flexSearchJs := . | fingerprint -}}
+          <script defer src="{{ $flexSearchJs.RelPermalink }}" integrity="{{ $flexSearchJs.Data.Integrity }}" crossorigin="anonymous"></script>
+        {{ end -}}
+      {{ end -}}
+    {{ end -}}
+    <script defer src="{{ $jsSearch.RelPermalink }}" integrity="{{ $jsSearch.Data.Integrity }}"></script>
+  {{- else -}}
+    {{- warnf `search type "%s" is not supported` $searchType -}}
+  {{- end -}}
+{{- end -}}