Turn /gift into a branch bundle so partner subpages can be added later

Converts content/gift/index.md to _index.md and extracts the shared
hero/form rendering into a partial (courses-body.html) used by both
single.html and a new list.html, so /gift renders identically but can
now hold real child pages like /gift/<partner>/.

The gift.reground.org vanity redirect already forwards any path
generically (redir https://reground.org/gift{uri}), so no
infrastructure change is needed to support future partnership URLs
like gift.reground.org/cheyenne once a matching page exists here.

layouts/courses/list.html

@@ -0,0 +1,3 @@
+{{ define "main" }}
+{{ partial "courses-body.html" . }}
+{{ end }}

layouts/courses/single.html

@@ -1,43 +1,3 @@
 {{ define "main" }}
-<section class="course-hero">
+{{ partial "courses-body.html" . }}
-  <h1>{{ .Title }}</h1>
-  {{ with .Params.hero_subhead }}<p class="course-subhead">{{ . }}</p>{{ end }}
-  {{ with .Params.hero_image }}<img class="course-hero-image" src="{{ . }}" alt="">{{ 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 }}

layouts/partials/courses-body.html

@@ -0,0 +1,41 @@
+<section class="course-hero">
+  <h1>{{ .Title }}</h1>
+  {{ with .Params.hero_subhead }}<p class="course-subhead">{{ . }}</p>{{ end }}
+  {{ with .Params.hero_image }}<img class="course-hero-image" src="{{ . }}" alt="">{{ 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>