feat: add prev/next article navigation with shell prompt style

Add top and bottom navigation between sequential articles with hacker aesthetic:
- Top nav: [visitor@danix.xyz articles]$ cd
- Bottom nav: [visitor@danix.xyz articles]$ ls ../
- Missing link shows dimmed placeholder (beginning/end)
- Only renders on articles, not static pages
- New partial: article-nav.html
- Styling: monospace prompt in accent color, hover links with transition

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/themes/danix-xyz-hacker/layouts/partials/article-nav.html b/themes/danix-xyz-hacker/layouts/partials/article-nav.html
new file mode 100644
index 0000000..d7f8ca3
--- /dev/null
+++ b/themes/danix-xyz-hacker/layouts/partials/article-nav.html
@@ -0,0 +1,46 @@
+{{ $page    := .page }}
+{{ $variant := .variant | default "bottom" }}
+{{ $prev := $page.PrevInSection }}
+{{ $next := $page.NextInSection }}
+
+{{/* Shell prompt command varies by position */}}
+{{ $cmd := "ls ../" }}
+{{ if eq $variant "top" }}
+  {{ $cmd = "cd" }}
+{{ end }}
+
+<nav class="article-nav {{ if eq $variant "bottom" }}mt-8{{ else }}mb-8{{ end }}"
+     aria-label="Article navigation">
+  <p class="article-nav-prompt" aria-hidden="true">
+    [visitor@danix.xyz articles]$ {{ $cmd }}
+  </p>
+  <div class="article-nav-links">
+    {{/* ---- Previous (left side) ---- */}}
+    {{ if $prev }}
+      <a href="{{ $prev.Permalink }}"
+         class="article-nav-link truncate max-w-[45%]"
+         rel="prev"
+         title="{{ $prev.Title }}">
+        ◄ {{ $prev.Title }}
+      </a>
+    {{ else }}
+      <span class="article-nav-placeholder" aria-label="Beginning of articles">
+        ◄ (beginning)
+      </span>
+    {{ end }}
+
+    {{/* ---- Next (right side) ---- */}}
+    {{ if $next }}
+      <a href="{{ $next.Permalink }}"
+         class="article-nav-link truncate max-w-[45%] text-right"
+         rel="next"
+         title="{{ $next.Title }}">
+        {{ $next.Title }} ►
+      </a>
+    {{ else }}
+      <span class="article-nav-placeholder text-right" aria-label="End of articles">
+        (end) ►
+      </span>
+    {{ end }}
+  </div>
+</nav>