Compose two already-migrated domains: a post is a relations-graph node
"blog:<slug>", and a "related" link is a symmetric pair of edges
(lib/relations). The post page shows a "Related posts" block; the edit page
gets an editor to add (by slug) and remove relations.
- host/blog-relate!/unrelate!/related: symmetric edges under kind "related";
related slugs = blog children, existence-filtered against ONE kv-keys read.
- post page: "Related posts" links block; edit page: related editor (remove
buttons + add-by-slug box).
- POST /:slug/relate, /:slug/unrelate — guarded browser routes (redirect to
login like the other write routes); relate validates the other post exists.
- delete cleans up a post's related edges (no dangling links).
IO ORDERING (the live 500 that conformance missed): host/blog--related-block/
-editor do durable reads (perform). Performing inside the quasiquote, via
unquote, while the page tree renders raised Sx_vm.VmSuspended under http-listen;
the in-memory conformance store never performs, so it passed. Fix mirrors
host/blog-home: do the reads in the handler's let bindings BEFORE the
quasiquote, and check related-existence against a single host/blog-slugs read
rather than a perform per candidate inside filter.
9 relate tests (guard, symmetry, render, no-op on missing, unrelate both ways,
delete cleanup). Verified live: relate -> Related block both ways; unrelate
clears it; posts without relations and the whole site stay 200.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>