Tick 13 and 13b, moving their text to todo-history.md

todo.md

@@ -218,24 +218,9 @@ proves 12, 13 spells 11's gaps in 12's grammar, and 12 rewrites code 4b and 4c c
   - [x] **12b — The inline form.**
   - [x] **12c — The block form.**
   - [x] **12d — The README, `MIGRATION.md` and the sweep.**
-- [ ] **13 — The schema's gap attributes (`0.2.0`).** Spell the attributes 11b pins as gaps, in
-      12's grammar, and empty the list.
-      **Settled** (the maintainer, 2026-09-13): a link `[text](url "title")` cannot hold takes the
-      directive mark `!adf:link[text]{attrs}` — one carrying `collection`, `id` or `occurrenceKey`,
-      or an `href` or `title` no CommonMark escape writes — and a directive link CommonMark could
-      spell is `unsupported-node-shape`. That leaves `unspellable-link` no cause, so it leaves
-      `ConvertErrorCode` in `0.2.0`, §8 recording the removal.
+- [x] **13 — The schema's gap attributes (`0.2.0`).**
   - [x] **13a — `rule` and `layoutSection`.**
-  - [ ] **13b — The directive link.** `link` spelled as above in both directions, with a round-trip
-        fixture per trigger, `spec/flavour.md`'s Marks section following; `unspellable-link` removed
-        from the code list, its `errors/` fixtures and the CommonMark suite's `unspellable`
-        exceptions it cures re-derived, the README's code table and its "not every document
-        converts back" guarantee following, and `MIGRATION.md` naming the removed code; the gap
-        list is empty. A round-trip fixture holds the shape 4.2's review left refused until then:
-        an autolink-shaped link under a directive mark whose href holds `\!adf:name{`. A link
-        opening a paragraph whose opening reads as a link reference definition, which 4.3 leaves
-        riding the carry, takes the directive link too, with its round-trip fixture (the
-        maintainer, 2026-09-15).
+  - [x] **13b — The directive link.**
 - [ ] **14 — The CommonMark subset's directory (`0.2.0`).** `src/markdown/` holds 16 source
       files at its root and 10 adds more there. The CommonMark subset moves under
       `src/markdown/commonmark/` — `backtick-runs.ts`, `commonmark-grammar.ts` as `grammar.ts`,