Pure tree walk: root → lanes → cards, level is position. Fail-fast with
path+reason for bad YAML, missing/malformed schema or order, newer
schema, rootless board; index-less folders skip with a collected+logged
warning; strays, hidden files, and symlinks ignored; board-level
deleted ignored with a warning; tombstones loaded and flagged. 17 tests.
Claude-Session: https://claude.ai/code/session_018BjQRYBR6jQja3jCRi5S3A
Immutable snapshot value types encoding the frontmatter tables: ItemID
wraps the exact folder name (not Foundation UUID, which uppercases);
lanes/cards carry FieldValue-typed fields, display-ordered children
including flagged tombstones, and their full FrontmatterDocument so
unknown and reserved keys ride along uninterpreted. Boards are
identified by rootURL — package folders are human-named, not UUIDs.
Claude-Session: https://claude.ai/code/session_018BjQRYBR6jQja3jCRi5S3A
Pure ordering math: append at max+1024, head-insert at min−1024,
midpoint insertion with precision-exhaustion detection (nil on ties and
rounding onto an endpoint), renumbering to whole multiples of 1024, the
shared display-order tie-break (order, then folder name), and
tombstone-excluding overloads. 18 tests.
Claude-Session: https://claude.ai/code/session_018BjQRYBR6jQja3jCRi5S3A
rzen