chore: coverage, autoload fix, and internal cleanup for org-drill

A batch of test-coverage and hardening work, squashed from the test-work branch.

Tests: deduplicated a colliding leitner-capture test name so make test-name loads again. Added SM2 assert-failure cases, the six basic multicloze variant delegations, the three English-side spanish-verb branches, and org-drill-current-scope branch coverage.

Fix: the entry-point commands (org-drill itself, cram-tree, tree, directory, resume, relearn-item, strip-all-data, merge-buffers) carried no autoload cookies, so M-x failed from a fresh install until something pulled the file in. They're autoloaded now.

Perf: org-drill-shuffle was quadratic because it indexed a list with elt on every swap. It runs a linear Fisher-Yates pass over a vector now, and it checks its argument is a list.

Feat: added org-drill-version, a constant plus an interactive command, so a bug reporter doesn't have to open the file header.

Refactor: extracted org-drill--format-tense-mood, shared by the two verb-conjugation presenters that each carried a copy.

Docs: explained the SM8 magic numbers in the simple8 helpers as empirical fits rather than tunable knobs.

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/test-org-drill-language-presenters.el b/tests/test-org-drill-language-presenters.el
index 6375b5f..da0a3a8 100644
--- a/tests/test-org-drill-language-presenters.el
+++ b/tests/test-org-drill-language-presenters.el
@@ -154,6 +154,25 @@
          (lambda (_) (setq reschedule-called t))))
       (should reschedule-called))))
 
+;;;; org-drill--format-tense-mood
+
+(ert-deftest test-org-drill-format-tense-mood-both ()
+  "With both tense and mood, the label names both."
+  (should (equal "past tense, subjunctive mood"
+                 (org-drill--format-tense-mood "past" "subjunctive"))))
+
+(ert-deftest test-org-drill-format-tense-mood-tense-only ()
+  "With only a tense, the label names the tense."
+  (should (equal "present tense" (org-drill--format-tense-mood "present" nil))))
+
+(ert-deftest test-org-drill-format-tense-mood-mood-only ()
+  "With only a mood, the label names the mood."
+  (should (equal "imperative mood" (org-drill--format-tense-mood nil "imperative"))))
+
+(ert-deftest test-org-drill-format-tense-mood-neither-is-nil ()
+  "With neither tense nor mood, there is no label."
+  (should (null (org-drill--format-tense-mood nil nil))))
+
 (provide 'test-org-drill-language-presenters)
 
 ;;; test-org-drill-language-presenters.el ends here