host: rel-kinds is a boot-populated VALUE, loads unrolled (live JIT iteration bug)

The serving-mode JIT dropped 3 of 4 relations when host/blog-rel-kinds map/for-each'd
a function-produced list (only the first survived) — so only one relation editor
rendered live. Restore slice 1's working shape: host/blog-rel-kinds is a VALUE the
boot populates (set! in load-rel-kinds!), and both the cache loads and the list build
are UNROLLED (no iteration over the relation list). Metadata still lives on the
relation-posts. conformance 287/287.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/host/blog.sx

@@ -102,23 +102,31 @@
 ;; rel-kinds / kind-symmetric? then read the cache (pure); the relation-posts stay
 ;; the durable source of truth. host/blog-load-rel-kinds! re-reads them.
 (define host/blog--rel-cache (dict))
-;; the relation slugs — a small fixed set. (Enumerating them from the graph via
-;; host/blog-in "relation" "is-a" proved fragile on the live store: that reduce over
-;; ALL edges returned a partial set. A static list is deterministic; the metadata
-;; still lives on the relation-posts. Add a relation here + a seed-rel! call.)
-(define host/blog--rel-slugs (fn () (list "related" "is-a" "subtype-of" "tagged")))
+;; cache one relation-post's :rel metadata (+ :kind), keyed by slug.
+(define host/blog--cache-rel!
+  (fn (kind)
+    (let ((m (get (host/blog-get kind) :rel)))
+      (when m (dict-set! host/blog--rel-cache kind (merge {:kind kind} m))))))
+;; host/blog-rel-kinds is a VALUE (the list of relation specs), populated at boot by
+;; load-rel-kinds! — like slice 1's static registry, which mapped fine on the live
+;; serving JIT. (Computing it as a function that map/for-each-es a function-produced
+;; list silently lost 3 of 4 relations on the live JIT — see plans/relations-as-posts.md
+;; / plans/jit-bytecode-correctness.md. Both the cache loads and the list build are
+;; therefore UNROLLED — no iteration over the relation list.) Metadata still lives on
+;; the relation-posts; add a relation = a seed-rel! + a line in each unrolled list.
+(define host/blog-rel-kinds (list))
 (define host/blog-load-rel-kinds!
   (fn ()
-    (for-each
-      (fn (kind)
-        (let ((m (get (host/blog-get kind) :rel)))
-          (when m (dict-set! host/blog--rel-cache kind (merge {:kind kind} m)))))
-      (host/blog--rel-slugs))))
+    (begin
+      (host/blog--cache-rel! "related")
+      (host/blog--cache-rel! "is-a")
+      (host/blog--cache-rel! "subtype-of")
+      (host/blog--cache-rel! "tagged")
+      (set! host/blog-rel-kinds
+        (list (get host/blog--rel-cache "related") (get host/blog--rel-cache "is-a")
+              (get host/blog--rel-cache "subtype-of") (get host/blog--rel-cache "tagged"))))))
 ;; spec = the cached :rel metadata + :kind; nil for a non-relation (relate validates).
 (define host/blog--kind-spec (fn (kind) (get host/blog--rel-cache kind)))
-(define host/blog-rel-kinds
-  (fn () (filter (fn (s) (not (nil? s)))
-           (map host/blog--kind-spec (host/blog--rel-slugs)))))
 (define host/blog--kind-symmetric?
   (fn (kind) (let ((s (host/blog--kind-spec kind))) (and s (get s :symmetric)))))
 
@@ -758,7 +766,7 @@
       ;; false: the initial edit page renders empty pickers (the load trigger fills
       ;; each), keeping this render cheap. The relate/unrelate FRAGMENT passes true.
       (map (fn (spec) (host/blog--relation-editor slug (get spec :kind) false))
-        (host/blog-rel-kinds)))))
+        host/blog-rel-kinds))))
 
 ;; ── read handlers ───────────────────────────────────────────────────
 ;; Post body is rendered per-block (a guarded HTML string) then injected raw.
@@ -972,7 +980,7 @@
           (begin
             (for-each (fn (o) (host/blog-unrelate! slug o kind)) (host/blog-out slug kind))
             (for-each (fn (o) (host/blog-unrelate! o slug kind)) (host/blog-in slug kind)))))
-      (host/blog-rel-kinds))))
+      host/blog-rel-kinds)))
 
 (define host/blog-delete-handler
   (fn (req)