v0.9.3

Nested lists now nest instead of flattening. An indented list item under another item previously became a sibling, so a three-level list rendered as one flat run with the structure silently discarded.

Ordered lists nested under unordered ones keep their own type, a shallower item of a different type is no longer absorbed into the deeper list, and four-space indentation is read as nesting rather than as a code block.

27/27 tests pass, including nine new nesting cases. Verified clean against Slate. Also drops a stray committed test artifact and gitignores *.actual.