{"id":"iter-descends-left-spine","text":"`__iter__` reaches the leftmost leaf by following `children[0]` at every internal level, then walks the sibling chain to `NO_SIBLING` to enumerate all keys in sorted order","truth_value":"IN","source":"entries/2026/05/29/topic-split-during-insert.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"iter-descends-left-spine","truth_value":"IN","reason":"premise"}]}}