test: add coverage for autolabor, cursecheck, fix-occupancy, preserve-tombs, nestboxes

[Alistair-Afton]

Summary

• Add in-engine regression tests for autolabor (help, enable gating, labor mode set/reset, unknown labor), cursecheck (map curse count, detail mode, help), fix-occupancy (fix_map/fix_tile dry-run and live verification), preserve-tombs (status, enable gating, now update), and nestboxes (status, burrow scoping, arg validation)
• autolabor, preserve-tombs, and nestboxes persist state; config.wrapper restores it after each test
• mode was considered but skipped: the plugin is commented out of plugins/CMakeLists.txt and not part of the build

Test plan

• Full in-engine suite green: 306/306 tests, 5123/5123 checks (Windows, DF 53.16)
• ci/lint.py clean on all new files