feat(lint-org): add four structural heading checkers org-lint misses

org-lint validates links, drawers, blocks, and babel, but not heading well-formedness. These four catch hand-edit defects it stays silent on: an indented heading demoted to body text (the task vanishes from the agenda and never archives), bare stars with no title, a malformed priority cookie org rejected, and a level-2 DONE/CANCELLED with no CLOSED line. All judgment-only and regex-based, wired in after the existing dated-header check. The last one pairs with the new aging step, which archives an undated completed task immediately.

I tightened the indented-heading check to two-or-more stars. The proposed one-or-more-stars regex flagged indented single-star lines, but an indented single * is a valid plain-list bullet, not a lost heading, so it false-positived on legitimate lists (confirmed: three valid bullets flagged). A ** is never a bullet, so an indented one is unambiguously a demoted heading. Added a test that a single-star list stays silent.

1 files changed, 76 insertions, 0 deletions

diff --git a/.ai/scripts/tests/test-lint-org.el b/.ai/scripts/tests/test-lint-org.el
index 242c35c..3b8a9bb 100644
--- a/.ai/scripts/tests/test-lint-org.el
+++ b/.ai/scripts/tests/test-lint-org.el
@@ -685,5 +685,81 @@ missing-rules violation."
          (judgments (lo-test--judgments (plist-get out :issues))))
     (should-not (member 'level-2-dated-header (lo-test--checkers judgments)))))
 
+;;; ---------------------------------------------------------------------------
+;;; structural heading checks (org-lint gaps)
+
+(defun lo-test--checker-lines (issues checker)
+  "Lines of judgment ISSUES whose :checker is CHECKER, document order."
+  (mapcar (lambda (i) (plist-get i :line))
+          (cl-remove-if-not
+           (lambda (i) (and (eq (plist-get i :kind) 'judgment)
+                            (eq (plist-get i :checker) checker)))
+           (reverse issues))))
+
+(ert-deftest lo-indented-heading-flags-leading-whitespace ()
+  "Error: a heading indented off column 0 is flagged (org demotes it to body)."
+  (let* ((out (lo-test--run "* Open\n  ** TODO indented and lost\n** TODO fine\n"))
+         (j (lo-test--judgments (plist-get out :issues))))
+    (should (member 'indented-heading (lo-test--checkers j)))
+    (should (= 1 (length (lo-test--checker-lines (plist-get out :issues)
+                                                 'indented-heading))))))
+
+(ert-deftest lo-indented-heading-skips-stars-inside-blocks ()
+  "Boundary: indented stars inside a #+begin_/#+end_ block are legitimate content."
+  (let* ((out (lo-test--run "* Open\n#+begin_example\n  ** not a heading\n#+end_example\n"))
+         (j (lo-test--judgments (plist-get out :issues))))
+    (should-not (member 'indented-heading (lo-test--checkers j)))))
+
+(ert-deftest lo-indented-heading-skips-single-star-list-bullets ()
+  "Normal: an indented single `*' is a valid plain-list bullet, not a demoted
+heading, so it is not flagged — only two-or-more indented stars are."
+  (let* ((out (lo-test--run "* Open\nintro line\n  * first bullet\n  * second bullet\n    * nested bullet\n"))
+         (j (lo-test--judgments (plist-get out :issues))))
+    (should-not (member 'indented-heading (lo-test--checkers j)))))
+
+(ert-deftest lo-empty-heading-flags-bare-stars ()
+  "Error: a line of bare stars with no title is flagged."
+  (let* ((out (lo-test--run "* Open\n** \n** TODO real\n"))
+         (j (lo-test--judgments (plist-get out :issues))))
+    (should (member 'empty-heading (lo-test--checkers j)))))
+
+(ert-deftest lo-malformed-priority-flags-lowercase-and-skips-valid ()
+  "Error + Normal: a lowercase/oversized cookie flags; a valid [#B] stays silent."
+  (let* ((bad (lo-test--run "* Open\n** TODO [#a] lowercase cookie\n** TODO [#BB] oversized\n"))
+         (ok (lo-test--run "* Open\n** TODO [#B] valid cookie\n"))
+         (jo (lo-test--judgments (plist-get ok :issues))))
+    (should (= 2 (length (lo-test--checker-lines (plist-get bad :issues)
+                                                 'malformed-priority-cookie))))
+    (should-not (member 'malformed-priority-cookie (lo-test--checkers jo)))))
+
+(ert-deftest lo-malformed-priority-skips-verbatim-cookie-in-title ()
+  "Boundary: a dated-log title quoting =[#D]= verbatim is not a real cookie."
+  (let* ((out (lo-test--run "* Open\n** TODO [#B] parent\n*** 2026-05-14 reprioritized =[#D]= -> =[#B]=\n"))
+         (j (lo-test--judgments (plist-get out :issues))))
+    (should-not (member 'malformed-priority-cookie (lo-test--checkers j)))))
+
+(ert-deftest lo-done-without-closed-flags-undated-level2 ()
+  "Error: a level-2 DONE with no CLOSED line is flagged; a dated one is not."
+  (let* ((bad (lo-test--run "* Resolved\n** DONE undated finished\nbody\n"))
+         (jb (lo-test--judgments (plist-get bad :issues)))
+         (ok (lo-test--run "* Resolved\n** DONE dated\nCLOSED: [2026-06-29 Mon]\n"))
+         (jo (lo-test--judgments (plist-get ok :issues))))
+    (should (member 'level2-done-without-closed (lo-test--checkers jb)))
+    (should-not (member 'level2-done-without-closed (lo-test--checkers jo)))))
+
+(ert-deftest lo-done-without-closed-ignores-deeper-levels ()
+  "Boundary: a level-3 DONE (a dated-log sub-entry) need not carry CLOSED."
+  (let* ((out (lo-test--run "* Resolved\n** DONE parent\nCLOSED: [2026-06-29 Mon]\n*** DONE nested no-closed\n"))
+         (j (lo-test--judgments (plist-get out :issues))))
+    (should-not (member 'level2-done-without-closed (lo-test--checkers j)))))
+
+(ert-deftest lo-structural-checks-silent-on-clean-file ()
+  "Normal: a well-formed file trips none of the four structural checkers."
+  (let* ((out (lo-test--run "* Open Work\n** TODO [#A] a task :tag:\n** DOING [#B] another\n* Resolved\n** DONE [#C] done\nCLOSED: [2026-06-29 Mon]\n"))
+         (checkers (lo-test--checkers (lo-test--judgments (plist-get out :issues)))))
+    (dolist (c '(indented-heading empty-heading malformed-priority-cookie
+                 level2-done-without-closed))
+      (should-not (member c checkers)))))
+
 (provide 'test-lint-org)
 ;;; test-lint-org.el ends here