fix(fusion_clock): code-review hardening [19.0.5.0.1]

- _cron_generate: per-rule savepoint isolation (one bad rule can't abort the
  whole daily batch)
- fclk_attach_recurrence: clear an existing recurrence first (no orphaned rule
  generating forever)
- fclk_apply_planner_cell: collapse split rows (search was limit=1 after the
  UNIQUE drop, orphaning extras)
- fclk_release_shift: reject non-posted/open shifts (raw-POST guard)
- delete_open_shift: report success=false when nothing was deleted + JS surfaces it
- _generate: log before removing an empty recurrence
Tests added for collapse, re-attach, draft-release.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

fusion_clock/tests/test_open_shift.py

@@ -75,6 +75,15 @@ class TestOpenShift(TransactionCase):
         self.assertTrue(sch.is_open)
         self.assertFalse(sch.employee_id)
 
+    def test_release_draft_shift_rejected(self):
+        emp = self.env['hr.employee'].create({'name': 'Drafty'})
+        future = date.today() + timedelta(days=30)
+        sch = self.S.create({
+            'employee_id': emp.id, 'schedule_date': future,
+            'start_time': 9.0, 'end_time': 17.0, 'state': 'draft'})
+        with self.assertRaises(ValidationError):
+            self.S.fclk_release_shift(sch, emp)
+
     def test_bulk_apply_to_many_employees(self):
         e1 = self.env['hr.employee'].create({'name': 'Bulk A'})
         e2 = self.env['hr.employee'].create({'name': 'Bulk B'})