Replace posts/001/slug nesting with issue taxonomy

Use Hugo's `issue = "issues"` taxonomy so each post carries
`issues: ["01"]` in frontmatter. Issue pages live at /issues/01/
with a dedicated _index.md holding title, season, and description.
The /issues/ archive page uses data/issues.json for forthcoming
entries that have no posts yet.

Layouts:
- layouts/issues/list.html → plate grid for a single issue term
- layouts/issues/terms.html → issues archive (new)
- _default/single.html → scopes grid to issue term page, back-link to /issues/01/
- baseof.html → ribbon links to /issues/01/, JSON island includes issue field
- partials/header.html → Issues link → /issues/

JS:
- lbClose() navigates to /issues/${issueId}/ on a single-post page
- lightbox meta panel shows linked Issue fact

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

layouts/issues/list.html

@@ -1,63 +1,45 @@
 {{ define "main" }}
-{{- $issues := .Site.Data.issues }}
+{{- $issueNum := .Params.issueNumber | default (printf "№ %s" .Title) }}
 <section class="hero" id="hero">
-  <div class="hero__eyebrow">Archive · Every issue</div>
-  <h1 class="hero__title">The <em>issues</em></h1>
-  <p class="hero__lede">Roux publishes one hundred photographs at a time, once a season. Each issue is a complete thing.</p>
+  <div class="hero__eyebrow">
+    {{ $issueNum }} · {{ .Params.season }}
+    · <a href="/issues/" style="border-bottom:1px solid currentColor;margin-left:6px">All issues</a>
+  </div>
+  <h1 class="hero__title"><em>{{ .Title }}</em></h1>
+  <p class="hero__lede">{{ .Params.description }}</p>
 </section>
 
-<div class="issues-grid">
-  {{- range $i, $iss := $issues }}
-  {{- $delay := mul $i 80 }}
-  {{- $isCurrent := eq $iss.status "current" }}
-  {{- $isForth   := eq $iss.status "forthcoming" }}
-
-  {{- if $isCurrent }}
-  <a href="/posts/" class="issue-card{{ if $isForth }} issue-card--forthcoming{{ end }}" style="--d:{{ $delay }}ms">
-  {{- else if $isForth }}
-  <div class="issue-card issue-card--forthcoming" style="--d:{{ $delay }}ms">
-  {{- else }}
-  <a href="/posts/" class="issue-card" style="--d:{{ $delay }}ms">
-  {{- end }}
-
-    <div class="issue-card__cover">
-      {{- if $isForth }}
-        <div class="issue-card__forth">
-          <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"/><polyline points="12 6 12 12 16 14"/></svg>
-          Forthcoming
-        </div>
-      {{- else }}
-        {{/* Use first post image as cover */}}
-        {{- $posts := where $.Site.RegularPages "Section" "posts" }}
-        {{- $first := index $posts 0 }}
-        {{- if $first }}
-          {{- $img := $first.Resources.GetMatch "*.png" }}
-          {{- if $img }}
-            {{- $cover := $img.Resize "480x720 webp" }}
-            <picture>
-              <source srcset="{{ $cover.RelPermalink }}" type="image/webp" />
-              <img src="{{ $cover.RelPermalink }}" alt="Issue {{ $iss.number }} cover" loading="lazy" />
-            </picture>
-          {{- end }}
-        {{- end }}
-      {{- end }}
-    </div>
-
-    <div class="issue-card__meta">
-      <div class="issue-card__num">{{ $iss.number }}</div>
-      <h2 class="issue-card__title">{{ $iss.title | replaceRE `^(.+)$` "$1" }}</h2>
-      <p class="issue-card__blurb">{{ $iss.blurb }}</p>
-      <div class="issue-card__foot">
-        <span>{{ $iss.season }}</span>
-        {{- if $isCurrent }}
-          <span class="issue-card__cta">Read the issue →</span>
-        {{- else if $isForth }}
-          <span class="issue-card__cta issue-card__cta--muted">Subscribe →</span>
+<section class="grid" id="grid" data-density="default">
+  {{- range $i, $p := .Pages }}
+    {{- $img := $p.Resources.GetMatch "*.png" }}
+    <a class="card"
+       href="{{ $p.RelPermalink }}"
+       style="--d:{{ mul (math.Min $i 18) 24 }}ms"
+       data-id="{{ $p.Params.plate }}"
+       data-slug="{{ $p.Params.slug }}">
+      <div class="card__frame">
+        {{- if $img }}
+          {{- $w := $img.Resize "600x900 webp" }}
+          <picture>
+            <source srcset="{{ $w.RelPermalink }}" type="image/webp" />
+            <img class="card__img"
+                 loading="{{ if lt $i 8 }}eager{{ else }}lazy{{ end }}"
+                 src="{{ $w.RelPermalink }}"
+                 alt="{{ $p.Title }}" />
+          </picture>
         {{- end }}
+        <span class="card__num">PLATE №{{ $p.Params.plate }}</span>
+        <span class="card__cat">{{ index ($p.Params.categories | default (slice "")) 0 }}</span>
       </div>
-    </div>
-
-  {{- if or $isCurrent (not $isForth) }}</a>{{- else }}</div>{{- end }}
+      <div class="card__meta">
+        <h2 class="card__title">{{ $p.Title }}</h2>
+        <div class="card__sub">
+          <span>{{ index ($p.Params.categories | default (slice "")) 0 }}</span>
+          {{- if $p.Params.tags }}<span class="dot"></span><span>{{ index $p.Params.tags 0 }}</span>{{ end }}
+        </div>
+        <p class="card__desc">{{ $p.Params.description }}</p>
+      </div>
+    </a>
   {{- end }}
-</div>
+</section>
 {{ end }}