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).

1 files changed, 31 insertions, 0 deletions

diff --git a/.ai/scripts/tests/test-lint-org.el b/.ai/scripts/tests/test-lint-org.el
index 3b8a9bb..d14879f 100644
--- a/.ai/scripts/tests/test-lint-org.el
+++ b/.ai/scripts/tests/test-lint-org.el
@@ -685,6 +685,37 @@ missing-rules violation."
          (judgments (lo-test--judgments (plist-get out :issues))))
     (should-not (member 'level-2-dated-header (lo-test--checkers judgments)))))
 
+;;; subtask-done-not-dated check (the inverse: level-3+ done keyword)
+
+(ert-deftest lo-subtask-done-not-dated-flags-level3 ()
+  "A level-3 DONE sub-task still carrying the keyword is flagged for conversion."
+  (let* ((out (lo-test--run
+               "* Open Work\n\n** TODO [#B] Parent\n*** DONE [#C] Sub-task done\nCLOSED: [2026-06-20 Sat 10:00]\nBody.\n"))
+         (judgments (lo-test--judgments (plist-get out :issues))))
+    (should (= 0 (plist-get out :fixes)))       ; judgment-only, never auto-fixed
+    (should (member 'subtask-done-not-dated (lo-test--checkers judgments)))))
+
+(ert-deftest lo-subtask-done-not-dated-flags-level4-cancelled ()
+  "A level-4 CANCELLED sub-task is flagged too."
+  (let* ((out (lo-test--run
+               "* Open Work\n\n** PROJECT [#B] Parent\n*** TODO Mid\n**** CANCELLED Deep abandoned\nCLOSED: [2026-06-20 Sat]\n"))
+         (judgments (lo-test--judgments (plist-get out :issues))))
+    (should (member 'subtask-done-not-dated (lo-test--checkers judgments)))))
+
+(ert-deftest lo-subtask-done-not-dated-ignores-level2 ()
+  "A level-2 DONE task is a top-level task, not a sub-task — this checker skips it."
+  (let* ((out (lo-test--run
+               "* Open Work\n\n** DONE [#B] Top-level\nCLOSED: [2026-06-20 Sat]\nBody.\n"))
+         (judgments (lo-test--judgments (plist-get out :issues))))
+    (should-not (member 'subtask-done-not-dated (lo-test--checkers judgments)))))
+
+(ert-deftest lo-subtask-done-not-dated-ignores-dated-and-lowercase ()
+  "An already-dated level-3 entry, and the word done in a title, are not flagged."
+  (let* ((out (lo-test--run
+               "* Open Work\n\n** TODO [#B] Parent\n*** 2026-06-20 Sat @ 10:00:00 -0400 landed\n*** TODO wrap the done cleanup\n"))
+         (judgments (lo-test--judgments (plist-get out :issues))))
+    (should-not (member 'subtask-done-not-dated (lo-test--checkers judgments)))))
+
 ;;; ---------------------------------------------------------------------------
 ;;; structural heading checks (org-lint gaps)