Comments on news posts: one forum discussion per post

oc:pages command in the forum extension, tools/forum_sync.py and
'make forum-sync' (run by deploy) keep data/forum_pages.json up to date;
post pages end with their discussion.

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

README.md

@@ -10,7 +10,7 @@ Static rebuild of old-computers.com with [Hugo](https://gohugo.io/) (0.158 or ne
 | `static/media/` | generated (copied images and documents) |
 | `data/slugs.json` | generated, keeps URLs stable between runs — do not delete |
 | `content/post/` | written by hand: news posts, see below |
-| `data/forum.json` | machine → forum thread map, written by the forum import (absent = no forum) |
+| `data/forum.json`, `data/forum_pages.json` | machine → forum thread and news post → forum thread maps, written by the forum import and by `make forum-sync` |
 | `forum/` | forum extension, local test stack, install notes |
 | `content/_index.md`, `layouts/`, `assets/`, `hugo.toml`, `tools/` | written by hand |
 | `build/`, `public/` | build output (`make build`, `hugo server`), not versioned |
@@ -32,6 +32,10 @@ banner, date, author and summary (`summary:` in the front matter, or the text be
 author's page, `listPosts` per page (20 by default). Posts are never touched by
 `make content`.
 
+With a forum, each published post gets a comment discussion, shown under the post. The
+discussion is created by `make forum-sync`, which `make deploy` runs first: it lists the posts,
+has the forum create the missing discussions and records them in `data/forum_pages.json`.
+
 ## Search
 
 Search runs in the visitor's browser on an index generated by [Pagefind](https://pagefind.app/)