The grid MVP was the only track reachable from the command line, so the
continuous room engine, channel packing, shove, and 45-degree routing were
unusable by anything shelling out to freeroute.
Add --engine {grid,exact,room} (default grid, unchanged behaviour) plus
--pack / --shove / --diagonal, and honour -mp on the tracks that implement
rip-up passes. Not every engine supports every pass; ENGINE_OPTIONS is the
matrix and an unsupported combination exits 2 with a message naming the
engines that do support the flag, rather than silently no-opping.
The pyproject declared a freeroute script but freeroute.cli was missing, so the
entry point was broken. Add it: reads a Specctra .dsn, routes (rip-up on by
default), writes SES. Accepts FreeRouting-compatible -de/-do flags so it can be
dropped in wherever 'java -jar freerouting.jar' was called.