Tick 3k and milestone 3, moving their text to todo-history.md

todo-history.md

@@ -154,9 +154,19 @@ The done `todo.md` items in full, as they were written. `todo.md` keeps a one-li
         2f raises what 1d's unspelled block separation costs: a single `localId` on a paragraph
         beside a plain one now refuses every container body that is a directive's — a panel, an
         expand, a table cell — where before 2f the attribute refused the document anyway.
-
-Under **3 — `markdownToAdf` (`0.1.0`)**:
-
+- [x] **3 — `markdownToAdf` (`0.1.0`).** Each sub-item lands the fixtures its own code reads, and
+      the runner grows a parse half as they do: readers for `corpus/normalization/` (setext,
+      indented code, loose lists, `*`/`+`
+      bullets, entity references, soft wraps — one-way, the markdown not canonical) and
+      `corpus/errors/` (a markdown input per named error, the code in a `.error` beside it) with
+      the first fixture each. `commonmark-subset/` cannot be the first to green — `::paragraph`
+      and `:hardBreak{}` sit in it — so 3b through 3f answer to their own tests and the one-way
+      fixtures they land, and 3g is where the first directory reads back. The raw-HTML element
+      mapping is empty until milestone 6, so at `0.1.0` every raw-HTML construct in input — a
+      block, an inline tag, a comment, a processing instruction — is a named error. Input is where
+      unbounded nesting actually arrives, so §11's 500 binds all three of the emitter's guards
+      here: block depth at 3c and again at 3f's container fences, inline and mark depth at 3f and
+      3i, a carried value's JSON at 3j, where `isJsonValue` already bounds it.
   - [x] **3a — The hierarchy.** Mechanical, ahead of the first parser file: `src/adf/` and
         `src/markdown/` (`html/` arrives with its first file, 6-7), the grammar module shared
         inside `markdown/`, and `emphasis-matching.ts` beside it — the parser reuses it whole,
@@ -386,6 +396,26 @@ Under **3 — `markdownToAdf` (`0.1.0`)**:
         `index.ts` gains `markdownToAdf` here, and the README's status line with it: this is the
         last parser chunk, so `parsingDirectories` becomes `emittingDirectories` and the whole
         corpus round-trips both ways — `0.1.0`'s proof, which 4 widens rather than replaces.
+  - [x] **3k — The CommonMark spec suite (`0.2.0`).** Checked in at `corpus/commonmark-spec/`,
+        pinned to the version it ships — the one `commonmark-grammar.ts` names for its start
+        conditions — `corpus/README.md` gaining the kind.
+        **Settled** (the maintainer, 2026-08-27): three checks an example must pass, the reference
+        HTML each ships read as corpus data — which adds no format and no direction (§1). §2's
+        canonical fixpoint: a named error, or markdown that parses and emits to itself byte for
+        byte. That HTML's text, tags stripped and entities decoded, against the parsed document's
+        concatenated `text`. And a count of the dozen elements the CommonMark subset covers
+        against the marks and nodes they map to — counting distinct mark types per text node, since
+        3e collapses a spelling nested inside its own kind and `*(*a*)*` is two `<em>` against one
+        `em`. The fixpoint alone is self-consistency a parser
+        returning the empty document passes, and the text alone one dropping every emphasis; the
+        counts close both. The exception list stays the maintainer's, and one entry is owed
+        already: 3h continues a list across the marker change CommonMark splits on, so an example
+        the reference HTML gives two `<ul>` counts one `bulletList`. One outcome is no
+        exception and must not be filed as one: a fixable §2 hole — valid CommonMark parsing to a
+        document `adfToMarkdown` refuses — which is what `corpus/unspellable/` held until 3c, 3e
+        and 3h landed their answers and emptied it. The permanent ones — a link destination or
+        title no escape spells, a paragraph opening with a code span — are the exceptions, named
+        by AGENTS.md §2.
 - [x] **5a — Rename to `@larvit/adf-codec` (`0.1.0`).** Before the first publish, the name being
       the published identity: `package.json` `name` and `repository`, the Gitea repo and its
       remote, the README title, §6's published-as line, the checkout directory.