content: by-id ops (update/delete) act tree-wide — fixes op-log no-op on nested blocks + 4 tests (750/750)

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

lib/content/tests/store.sx

@@ -151,3 +151,30 @@
   "op-log media type"
   (blk-type (doc-find (content/head B3 "rich") "v"))
   "media")
+
+;; ── op-log update/delete reach NESTED blocks (tree-wide by id) ──
+(content-bootstrap-section!)
+(define B4 (persist/open))
+(content/commit!
+  B4
+  "nest"
+  (op-insert (mk-section "sec" (list (mk-text "n" "orig"))) nil)
+  1)
+(content/commit! B4 "nest" (op-update "n" "text" "edited") 2)
+(content-test
+  "op-log nested update"
+  (str (blk-send (doc-deep-find (content/head B4 "nest") "n") "text"))
+  "edited")
+(content-test
+  "op-log nested update tree intact"
+  (doc-tree-ids (content/head B4 "nest"))
+  (list "sec" "n"))
+(content/commit! B4 "nest" (op-delete "n") 3)
+(content-test
+  "op-log nested delete"
+  (doc-tree-ids (content/head B4 "nest"))
+  (list "sec"))
+(content-test
+  "op-log nested delete via content/at seq2"
+  (doc-tree-ids (content/at B4 "nest" 2))
+  (list "sec" "n"))