Changes touching this path

• loot lanes now reads the shared graph and scans the object directory once per board draw rather than once per registered lane: a new DagRepo::load_positions_from reads the position files of every lane first and the shared half once after them, so each row keeps the read order load_from_needing documents while every row reports against one moment of the shared store. that is the decision the ticket asked for, recorded on peek_lanes with its reasons, among them that option c cannot help because a row needs both the graph and the objects. a single load now reads the working change before the graph, the order that doc states. on a scratch repo with twelve lanes and a 4.9 MB graph the board went from 237 to 190 ms, paired in both orders with loot status flat as the control, and its porcelain and json output is unchanged apart from heartbeat age. a new board test relating the store file reads of the board to those of its rows built one at a time went red on the unchanged code and with per-row loads put back (0 passed, 1 failed each), and an engine test comparing a batch load with solo loads went red with the mixed-store refusal removed and with one position half reused (0 passed, 1 failed each). the perf gate reads no move, CONTEXT.md follows, and the workspace suite is green (#1782) caed7d82 · dbf3dbe6…

Renames are not followed. loot's tree maps a path to an address, so a rename is a delete and an add. This list is the history of the name, not of the bytes.