[ctoth]

area-reader atlas <question> <files or directories> loads several area files into one set and answers, as text or --json:

• summary: per-area counts and overlapping vnum ranges.
• reach --from VNUM: rooms reachable by exits, rooms that can walk back, areas nothing leads into; --with-portals and --with-progs add non-walking links and show the difference.
• links: the area graph and one-way links.
• dangling: references to vnums no file defines (exits, keys, resets, shop keepers, specials, mob programs, portals, rooms named in programs).
• depends: which other areas each area needs, and why.
• path A B, find TEXT.

cli.load_area and the single-file JSON output are unchanged. atlas as the first argument now selects the subcommand.

On the stock ROM set in test/rom from room 3001: 3126 rooms, 3082 reachable, 2901 can walk back; quifael is the only area nothing leads into.

Limits: expects the ROM/Merc model shape and was run only on ROM files; program links follow transfer/gtransfer only.