Diagnosed (owner report 2026-10-06, 'splattered from the middle on
every navigation'): the canvas's world is 350 nodes — 262 stored
propositions + 88 derived arg_ implication nodes the chain arrows
bend through — but the drag-commit sanitizer accepted only stored
proposition ids, and writePositions REPLACES the file: every
drag-commit purged the arg_ entries, so every mount re-seeded them
on a ~1306-unit ring (seedMissingNodePositions) — arrows streaking
out of the middle, bbox inflated, fit zoomed out. A drag annealed
them back (impLinks springs), the commit stripped them again.
Fix: the sanitizer's known set = deriveView(getGraph()).nodes —
propositions AND arg_ ids (stable: minted from the chain ledger).
The grew-check becomes the honest test — some CURRENT view node
absent from the payload (a merge landed mid-drag) → exactly one
absorbing settle; full coverage → none (the old proposition-count
comparison broke once args counted).
Live ledger backfilled once: 88 arg_ positions seeded at their
chains' centroids, propositions byte-identical (no settle, no
re-anneal). Pinned in tests/commit-positions.test.ts (hermetic
LH_DATA_DIR): args persist, unknown ids drop, no-settle on full
coverage, absorbing settle on a stale payload, garbage sanitizing.
