content: relative block reorder (move.sx) + 11 tests (668/668)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/content/tests/move.sx

@@ -0,0 +1,63 @@
+;; Extension — relative block reorder.
+
+(st-bootstrap-classes!)
+(content/bootstrap!)
+
+(define
+  d
+  (doc-append
+    (doc-append
+      (doc-append (doc-empty "d") (mk-text "a" "A"))
+      (mk-text "b" "B"))
+    (mk-text "c" "C")))
+
+;; ── move-before ──
+(content-test
+  "move-before"
+  (doc-ids (content/move-before d "c" "a"))
+  (list "c" "a" "b"))
+(content-test
+  "move-before mid"
+  (doc-ids (content/move-before d "c" "b"))
+  (list "a" "c" "b"))
+(content-test "move-before immutable" (doc-ids d) (list "a" "b" "c"))
+
+;; ── move-after ──
+(content-test
+  "move-after"
+  (doc-ids (content/move-after d "a" "b"))
+  (list "b" "a" "c"))
+(content-test
+  "move-after last"
+  (doc-ids (content/move-after d "a" "c"))
+  (list "b" "c" "a"))
+
+;; ── move-to-front / back ──
+(content-test
+  "move-to-front"
+  (doc-ids (content/move-to-front d "c"))
+  (list "c" "a" "b"))
+(content-test
+  "move-to-back"
+  (doc-ids (content/move-to-back d "a"))
+  (list "b" "c" "a"))
+(content-test
+  "front already first"
+  (doc-ids (content/move-to-front d "a"))
+  (list "a" "b" "c"))
+
+;; ── no-ops ──
+(content-test
+  "missing id no-op"
+  (doc-ids (content/move-before d "zzz" "a"))
+  (list "a" "b" "c"))
+(content-test
+  "missing target no-op"
+  (doc-ids (content/move-before d "a" "zzz"))
+  (list "a" "b" "c"))
+
+;; ── render after move ──
+(content-test
+  "render after move"
+  (asHTML (content/move-after d "a" "c"))
+  "<p>B</p><p>C</p><p>A</p>")