content: render boundary (asHTML/asSx polymorphic) + 29 tests

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

plans/content-on-sx.md

@@ -19,7 +19,7 @@ injected adapter, not core.
 
 ## Status (rolling)
 
-`bash lib/content/conformance.sh` → **78/78** (Phase 1: blocks + doc)
+`bash lib/content/conformance.sh` → **107/107** (Phase 1: blocks + doc + render)
 
 ## Ground rules
 
@@ -59,7 +59,7 @@ lib/content/api.sx ── (content/edit) (content/render) (content/history) ─
 ## Phase 1 — Block document model
 - [x] `block.sx` — typed block objects
 - [x] `doc.sx` — ordered tree, apply edit op, structural moves
-- [ ] `render.sx` — block tree → HTML/SX
+- [x] `render.sx` — block tree → HTML/SX
 - [ ] `api.sx` + tests + scoreboard + conformance.sh
 
 ## Phase 2 — Op log + versioning
@@ -77,6 +77,13 @@ lib/content/api.sx ── (content/edit) (content/render) (content/history) ─
 
 ## Progress log
 
+- 2026-06-07 — Phase 1 `render.sx`: render boundary as polymorphic message
+  dispatch. Every block and `CtDoc` answers `asHTML` / `asSx`; the document
+  folds children via Smalltalk `inject:into:` (works on raw SX lists), so
+  `(asHTML doc)` / `(asSx doc)` are pure sends with zero type-switching in SX.
+  Lists/headings render in Smalltalk source. No HTML escaping yet (noted in
+  render.sx — boundary concern before untrusted content). 29 tests; suite
+  107/107.
 - 2026-06-06 — Phase 1 `doc.sx`: ordered block document (`CtDoc`) as a
   Smalltalk object holding an ordered block sequence. Edit ops are data dicts
   (`insert`/`update`/`move`/`delete`) with `op-*` constructors; `doc-apply` /