Initial scaffold: submissions page + reader-magnet stub

Mirrors twosquirrelspress-site's submissions form and
michaelferrara-site's gift/course-enroll pattern. Gift page content,
cover art, and the download file are stubs until the real
reader-magnet is ready.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

layouts/courses/single.html

@@ -0,0 +1,43 @@
+{{ define "main" }}
+<section class="course-hero">
+  <h1>{{ .Title }}</h1>
+  {{ with .Params.cover_image }}<img class="course-cover" src="{{ . }}" alt="{{ $.Title }} cover">{{ end }}
+  {{ with .Params.hero_subhead }}<p class="course-subhead">{{ . }}</p>{{ end }}
+
+  {{ partial "course-enroll-form.html" (dict "id" "top" "page" .) }}
+
+  {{ with .Params.social_proof }}<p class="course-social-proof">{{ . }}</p>{{ end }}
+</section>
+
+{{ if or .Params.credibility_heading .Params.credibility_bullets }}
+<section class="course-credibility">
+  {{ with .Params.credibility_heading }}<h2>{{ . }}</h2>{{ end }}
+  {{ with .Params.credibility_bullets }}
+  <ul class="course-bullets">
+    {{ range . }}<li>{{ . | markdownify }}</li>{{ end }}
+  </ul>
+  {{ end }}
+</section>
+{{ end }}
+
+{{ if or .Params.curriculum_heading .Params.curriculum_items }}
+<section class="course-curriculum">
+  {{ with .Params.curriculum_heading }}<h2>{{ . }}</h2>{{ end }}
+  {{ with .Params.curriculum_intro }}<p>{{ . }}</p>{{ end }}
+  {{ with .Params.curriculum_items }}
+  <ol class="course-curriculum-list">
+    {{ range . }}
+    <li>{{ with .label }}<span class="course-day-label">{{ . }}</span> {{ end }}{{ .text | markdownify }}</li>
+    {{ end }}
+  </ol>
+  {{ end }}
+</section>
+{{ end }}
+
+{{ .Content }}
+
+<section class="course-repeat-cta">
+  {{ with .Params.repeat_cta_heading }}<h2>{{ . }}</h2>{{ end }}
+  {{ partial "course-enroll-form.html" (dict "id" "bottom" "page" .) }}
+</section>
+{{ end }}