Content as Markdown with YAML front matter

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YDRjtmAiNpo5mK5N3d7QwZ

README.md

@@ -12,6 +12,9 @@ Static rebuild of old-computers.com with [Hugo](https://gohugo.io/) (0.158 or ne
 | `content/_index.md`, `layouts/`, `assets/`, `hugo.toml`, `tools/` | written by hand |
 | `public/` | build output, not versioned |
 
+Content pages are Markdown with YAML front matter and can be corrected by hand, but a later
+`make content` overwrites them: lasting fixes belong in the extraction repository.
+
 ## Usage
 
     make content   # regenerate from ../oc (OC=path to use another location)