- Per-step rdtsc timing: ZGCStats returns max_step_us and atomic_us
- AllocBench /zgcstats frame shows step/atomic timing with color coding
- /gccompare command for timing forced GC cycles
- Honor lua_setgcthreshold forced collections (collectgarbage() with low
threshold now triggers GC instead of being silently ignored)
- Disable luaalloc in weirdperformance when luagc is active (no conflict)
- Closures go to grayagain (covers all upvalue mutation paths)
