Players submit their moves against the same board state. Implement the referee so one accepted move cannot accidentally change how a competing move is judged during that turn.
Build the implementation in Rust under /app, with /app/run.sh as its entry point. Read one JSON request from standard input and write one JSON result to standard output. Input has positions mapping player IDs to unique [x,y] integer cells and moves mapping a subset of IDs to adjacent destination cells (Manhattan distance at most one). A move fails if its target was occupied by another player at turn start, even if that player moves away, or if multiple players propose the same target. Players without moves remain still. Return final positions sorted by ID. Unknown movers, duplicate initial cells and illegal distances must be rejected.
Reject inputs that violate an explicit validation rule with exit status 2, no standard output, and {"error":"invalid_input"} on standard error. For valid input, exit with status 0. Keep the implementation reusable for new inputs; it must work offline and must not depend on the example data being the only data it receives.
Repair or replace the unfinished /app/run.sh and add source files under /app. Malformed JSON must use the same invalid-input response. Do not read /tests or /oracle from the application.