Adds EditorApp::randomPopulateZone(creatureCount, objectCount, seed)
and a Generate-menu submenu with sliders for both counts plus a
seed input. Same logic and bestiary as the --random-populate-zone
CLI: 12 creature templates with level jitter, 5 placeholder WMO
prop types with randomized rotation/scale.
Spawns are placed within the loaded tile's world bbox, marked
dirty + auto-save pending so the populated content persists across
restarts.
The CLI command remains for CI / scripting / batch workflows; the
menu serves designers who want to populate from the GUI without
context-switching to a terminal.
Same-seed reproducibility: a hover hint reminds the user that the
seed determines the output deterministically.
89dacba666