Adds tools/gen_sideb.py — one data-driven builder replacing the copy-pasted
gen_missionN.py pattern — and tools/smoketest.sh, which reports
PASS/FAIL/DISPLAY_UNAVAILABLE instead of the process-is-alive check that has
produced false passes twice now.
NOT verified in-game: the display went to sleep mid-session. Static checks all
pass (luac, check-yaml 0 errors, map refresh, check_assets, make) and the
already-verified m03 hangs identically, confirming it is environmental.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>