feat(todo-cleanup): add --convert-subtasks dated-rewrite mode

Rewrites every level-3+ DONE/CANCELLED/FAILED heading into a dated event-log entry from its CLOSED cookie, enforcing the todo-format depth rule that interactive closes and --archive-done (level-2 only) leave unapplied. A new lint-org checker (subtask-done-not-dated) flags stragglers, and the clean-todo, wrap-up, open-tasks, and task-review workflows now run the converter before archiving.

Removing the CLOSED cookie keeps a DEADLINE or SCHEDULED cookie that shares its planning line, rather than dropping the whole line.

From the .emacs.d handoff (2026-07-01 convert-subtasks bundle).

4 files changed, 38 insertions, 8 deletions

diff --git a/.ai/workflows/clean-todo.org b/.ai/workflows/clean-todo.org
index dd33056..a1b2af5 100644
--- a/.ai/workflows/clean-todo.org
+++ b/.ai/workflows/clean-todo.org
@@ -27,7 +27,17 @@ Deletes bogus =- State "X" from "X" [date]= log lines (state didn't actually cha
 
 To preview without writing, run =--check= first: =emacs --batch -q -l .ai/scripts/todo-cleanup.el --check todo.org=.
 
-** Step 2: Archive completed work
+** Step 2: Convert done sub-tasks to dated entries
+
+#+begin_src bash
+emacs --batch -q -l .ai/scripts/todo-cleanup.el --convert-subtasks todo.org
+#+end_src
+
+Rewrites every heading at level 3 or deeper whose TODO state is DONE/CANCELLED/FAILED into a dated event-log entry (=<stars> YYYY-MM-DD Day @ HH:MM:SS -ZZZZ <text>=), dropping the keyword, priority cookie, and tags, and removing the =CLOSED:= line. Enforces the depth rule that a completed sub-task becomes dated history — a shape interactive org closes and =--archive-done= (level-2 only) leave unapplied. Timestamp comes from each entry's =CLOSED= cookie; heading text kept verbatim; idempotent; a done sub-task with no parseable =CLOSED= is flagged and left alone. Run before archiving so a parent's sub-tasks are already dated when it moves. Capture the output.
+
+To preview without writing: =emacs --batch -q -l .ai/scripts/todo-cleanup.el --convert-subtasks --check todo.org=.
+
+** Step 3: Archive completed work
 
 #+begin_src bash
 emacs --batch -q -l .ai/scripts/todo-cleanup.el --archive-done todo.org
@@ -37,10 +47,11 @@ Moves every level-2 subtree whose TODO state is DONE or CANCELLED out of the "Op
 
 To preview the moves without writing: =emacs --batch -q -l .ai/scripts/todo-cleanup.el --archive-done --check todo.org=.
 
-** Step 3: Summarize
+** Step 4: Summarize
 
-Report to Craig from the two captured outputs:
+Report to Craig from the three captured outputs:
 - Hygiene: how many bogus state-log lines were deleted; any orphan-planning warnings (file:line + heading), or "none".
+- Convert: how many done sub-tasks were rewritten to dated entries (heading + line), any flagged for no =CLOSED= date, or "nothing to convert".
 - Archive: how many subtrees moved and which (heading + line), or "nothing to move" / the skip reason if a section was missing or ambiguous.
 - If the file changed, note that =todo.org= now has an uncommitted edit — review =git diff -- todo.org= and commit it (in this repo's commit style) if it looks right. If nothing changed, say so and stop.
 
@@ -49,7 +60,7 @@ Don't auto-commit. The summary is the review point; Craig decides whether the di
 * Principles
 
 - *Both passes apply, not just preview.* The workflow is invoked because cleanup is wanted. Use the =--check= variants only when Craig asks for a dry run.
-- *Two passes, two invocations.* =--archive-done= is its own mode and does not run the hygiene pass; run both.
+- *Separate modes, separate invocations.* =--convert-subtasks=, =--archive-done=, and the hygiene pass are each their own mode and don't run the others; run all three.
 - *Never auto-commit todo.org.* Surface the diff and let Craig commit it. The cleanup is a working-tree change, fully reversible until committed.
 - *Trust the script.* It's fast and idempotent; if there's nothing to do, it reports zero and exits clean. No pre-checks.
 
diff --git a/.ai/workflows/open-tasks.org b/.ai/workflows/open-tasks.org
index 4ba29dd..02a0847 100644
--- a/.ai/workflows/open-tasks.org
+++ b/.ai/workflows/open-tasks.org
@@ -23,15 +23,16 @@ Don't route "task review" / "review tasks" here — those trigger the hygiene ha
 
 * Phase A: Data Gathering (both modes)
 
-** Phase A pre-step — archive any freshly-DONE tasks
+** Phase A pre-step — normalize freshly-closed tasks
 
-Before reading =todo.org=, run the cleanup script's archive-done sweep so completed level-2 subtrees move from =* $Project Open Work= to =* $Project Resolved=:
+Before reading =todo.org=, run two cleanup sweeps so the read reflects current state. First convert any done sub-tasks to dated entries, then archive completed level-2 subtrees from =* $Project Open Work= to =* $Project Resolved=:
 
 #+begin_src bash
+emacs --batch -q -l .ai/scripts/todo-cleanup.el --convert-subtasks todo.org
 emacs --batch -q -l .ai/scripts/todo-cleanup.el --archive-done todo.org
 #+end_src
 
-Costs a few hundred milliseconds. Without it, a task that completed earlier in the session sits as =** DONE= under Open Work until the next =clean-todo= or wrap-up pass, and Next Mode would surface it as a "what's next" candidate. The sweep makes Phase A's read of =todo.org= reflect current state.
+Costs a few hundred milliseconds. Without the archive sweep, a task that completed earlier in the session sits as =** DONE= under Open Work until the next =clean-todo= or wrap-up pass, and Next Mode would surface it as a "what's next" candidate. The convert sweep runs first so a completed parent's sub-tasks are already dated when it archives; it also keeps interactive level-3 closes from lingering as DONE keywords. Together they make Phase A's read of =todo.org= reflect current state.
 
 Skip the sweep if the workflow is invoked in an explicit read-only or dry-run context. Default is to run it.
 
diff --git a/.ai/workflows/task-review.org b/.ai/workflows/task-review.org
index 69e172d..7b6327b 100644
--- a/.ai/workflows/task-review.org
+++ b/.ai/workflows/task-review.org
@@ -96,6 +96,8 @@ The exact date string matters: =task-review-staleness.sh= and the wrap-up health
 
 Follow the completion rules in [[file:../../claude-rules/todo-format.md][todo-format.md]]. A killed top-level =**= task stays task-shaped: change the keyword to =CANCELLED=, add a =CLOSED: [YYYY-MM-DD Day]= line under the heading (generate with =date "+%Y-%m-%d %a"=), and leave the priority and tags intact. It's then a candidate for =--archive-done= at the next cleanup. Don't stamp =:LAST_REVIEWED:= on a kill — it's leaving the review pool anyway.
 
+A killed *sub-task* (=***= or deeper, under a parent task) instead becomes a dated event-log entry per the depth rule — but you don't have to hand-format it here. =todo-cleanup.el --convert-subtasks= (run in the =clean-todo= and wrap-up cleanup passes) rewrites any level-3+ DONE/CANCELLED/FAILED heading into its dated form mechanically from the =CLOSED= cookie, so a keyword-plus-=CLOSED= close at depth gets normalized on the next cleanup rather than lingering. =lint-org.el= flags any that slip through (checker =subtask-done-not-dated=).
+
 * Phase D: Close out
 
 When the batch is done (or Craig calls it early):
diff --git a/.ai/workflows/wrap-it-up.org b/.ai/workflows/wrap-it-up.org
index 5d2cdd2..4fa5a3a 100644
--- a/.ai/workflows/wrap-it-up.org
+++ b/.ai/workflows/wrap-it-up.org
@@ -137,6 +137,22 @@ Run the report-only variant first if you want to see what would change without w
 emacs --batch -q -l .ai/scripts/todo-cleanup.el --check todo.org
 #+end_src
 
+*** Convert done sub-tasks to dated entries
+
+#+begin_src bash
+[ -f todo.org ] && emacs --batch -q -l .ai/scripts/todo-cleanup.el --convert-subtasks todo.org
+#+end_src
+
+=--convert-subtasks= rewrites every heading at level 3 or deeper whose TODO state is DONE/CANCELLED/FAILED into a dated event-log entry (=<stars> YYYY-MM-DD Day @ HH:MM:SS -ZZZZ <text>=), dropping the keyword, priority cookie, and tags, and removing the now-redundant =CLOSED:= line. This enforces the =todo-format.md= depth rule that a completed *sub-task* (a heading under a parent task) becomes dated history, not a lingering DONE keyword — a shape an interactive org close (=org-log-done= → DONE + CLOSED) never applies and =--archive-done= (level-2 only) never reaches. The timestamp comes from each entry's own =CLOSED= cookie; a date-only close yields =00:00:00=. Heading text is kept verbatim. Idempotent (an already-dated heading has no keyword to match), and a done sub-task with no parseable =CLOSED= is flagged and left alone rather than stamped with a fabricated date.
+
+Run this *before* =--archive-done= so that when a completed level-2 parent is archived, its sub-tasks already carry their dated form. Any rewrites show up in the wrap-up commit's diff for review before push.
+
+Preview without writing:
+
+#+begin_src bash
+emacs --batch -q -l .ai/scripts/todo-cleanup.el --convert-subtasks --check todo.org
+#+end_src
+
 *** Archive completed work
 
 #+begin_src bash
@@ -536,7 +552,7 @@ Before considering wrap-up complete:
 - [ ] The Summary ends with the =KB: promoted N / consulted yes-no= line (promotion check ran)
 - [ ] File renamed to =.ai/sessions/YYYY-MM-DD-HH-MM-description.org=
 - [ ] =.ai/session-context.org= no longer exists
-- [ ] =todo-cleanup.el= ran — hygiene pass + =--archive-done= + =--sync-child-priority= (if =todo.org= exists at project root)
+- [ ] =todo-cleanup.el= ran — hygiene pass + =--convert-subtasks= + =--archive-done= + =--sync-child-priority= (if =todo.org= exists at project root)
 - [ ] =lint-org.el= ran on =todo.org= — mechanical fixes applied, judgments appended to follow-ups file (if =todo.org= exists)
 - [ ] Any orphan-planning-line warnings reviewed (fix or accept)
 - [ ] Inbox carries nothing but expected pipeline artifacts (=.gitkeep=, =lint-followups.org=, =PROCESSED-*= prefixes), OR each remaining handoff has an explicit deferral logged in the valediction