make dev passed --watch to a build.js that read no arguments, so it built once and exited. build.js --watch now builds, then builds again after every change to a file under src/, manifest/ or icons/, until interrupted; any other argument fails. Each directory gets its own watcher, because Node's recursive watch on Linux loses a file that an editor saves by renaming a new copy over it. A watch build writes no build receipt and cannot be verified; README.md and the Makefile say so and point to make build. Model: opus-5-5