Swap published columns for 24 entries from random.md

Retract the seven published columns into drafts/ and promote the 24 per-date
entries split out of Notes/random.md. Bodies are verbatim; titles, subjects
and slugs are new.

Make publication a matter of location. Notes/Notes.11tydata.js gives anything
under Notes/ permalink: false unless tagged `column`; drafts/drafts.11tydata.js
renders drafts at their real permalink under `yarn dev` and excludes them from
collections entirely in a build, so no template can surface one. Publishing is
now `git mv drafts/<file> columns/`, and moving it back retracts it.

Untagged notes were previously rendered into _site/ and deployed — including
Notes/random.md, which was live at /Notes/random/.

drafts/index.njk

@@ -0,0 +1,26 @@
+---
+layout: base.njk
+title: Drafts
+permalink: /drafts/
+eleventyExcludeFromCollections: true
+---
+
+<h1>Drafts</h1>
+
+<p>Unpublished. Visible on the dev server only — <code>yarn build</code> emits
+none of this. Promote one with <code>git mv drafts/&lt;file&gt; columns/</code>.</p>
+
+{%- if collections.drafts.length %}
+<ul class="toy-list">
+  {%- for draft in collections.drafts %}
+  <li>
+    <a href="{{ draft.url }}">{{ draft.data.title | inlineMarkdown | safe }}</a>
+    <span class="toy-description">
+      {{ draft.date | isoDate }} · {{ draft.data.tags | reject("equalto", "column") | join(", ") }}
+    </span>
+  </li>
+  {%- endfor %}
+</ul>
+{%- else %}
+<p>No drafts.</p>
+{%- endif %}