When unchecking a child from the done section, it stayed at the end of
the items array (where done items live), appearing as the last active
item instead of under its parent. Now repositions after the last sibling
or parent in the array.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Extract checklist logic into testable utility module:
- ChecklistItem type with parentId field for single-level nesting
- parseChecklist/serializeChecklist with 2-space prefix for children
- toggleItemWithCascade: parent check/uncheck cascades to children
- indentItem/outdentItem with sibling adoption rules
- 21 unit tests covering parse, serialize, toggle, indent, outdent
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
