Nominate related pages with Markdown links, not siblings macros

Drops the `wiki.siblings` frontmatter block from all eight files that carried
one — six of them declared it empty — and replaces the two live `ALL_CAPS`
placeholders with ordinary relative Markdown links:

  see PULSE_DEV.  ->  see [Dev gibberish](pulse_dev.md).

Both now resolve to real wikilinks at publish time, and both read as links in
Gitea's blob view instead of as a naked token in the middle of a sentence.

Requires the matching renderer change in novoyuuparosk-auto-wiki; the macro
substitution it depended on no longer exists.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -17,6 +17,31 @@ Song pages are auto-published to <https://wiki.novoyuuparosk.org> by the
 In short: a file is published when its frontmatter has `wiki.publish: true`
 and it isn't under `wip/`. The `title` field becomes the wiki page name.
 
+## Linking to another song page
+
+Write an ordinary relative Markdown link. There is nothing to declare in the
+frontmatter:
+
+```markdown
+For more behind-the-scene shenanigans, see [Dev gibberish](pulse_dev.md).
+```
+
+At publish time the `.md` target is swapped for the target file's own `title`,
+giving a proper wikilink — so renaming a page means editing its `title` and
+nothing else. The link keeps working in Gitea's blob view and in any editor
+preview, because it is just a link.
+
+Two things to know:
+
+- The target must be published too (`wiki.publish: true`, outside `wip/`).
+  Linking to a file does **not** publish it; an unresolvable link fails the CI
+  run instead of quietly turning into plain text.
+- Links do not work inside a ` ```columns ` fence — that block is verbatim by
+  design. Put them in ordinary prose.
+
+This replaces the old `wiki.siblings` frontmatter block and its `ALL_CAPS`
+placeholders, which are gone.
+
 ## Side-by-side lyrics (columns shorthand)
 
 To lay two (or more) versions of a song next to each other — e.g. an original