fixrun.log — DF-5793 fix validation, patched kernel #2 (krate .freq=1 + PCATCH/EINTR)

a) patched directed run (kernel #1, PCATCH present, freq v1=10):
$ /home/maxx/dup_directed 10
spammer: attempts=225 slow=10 err=10 errno_last=4(Interrupted system call)
directed: pipes=3813707
   -> dup2() now returns EINTR instead of parking forever; wait is interruptible.

b) final fix (freq=1), 4 concurrent rigs x 10s (kernel #2):
$ for i in 1 2 3 4; do dup_directed 10 & done; sleep 13
$ dmesg | grep -c "target descriptor"
10
   -> krate caps output at 1 line/sec system-wide (unpatched: ~10 lines/10s
      per thread measured => ~40 expected from 4 rigs).

c) SIGKILL latency while parked (kernel #2):
patched SIGKILL-to-death sec: 0
warnings-total: 13
   -> immediate death vs 1s on stock.

fix_status: fixed