Lite Blue 1.2.1

Lite Blue 1.2.1 — a timing bugfix.

• Fix a 32-bit overflow in elapsed_ms(): searches longer than about two
  seconds on AIX reported a negative time and a bogus nps, and the same
  value feeds time management, so a long time-controlled search could overrun.

Found on obsidian while checking the site's node-rate figure — which turned out
to be stale anyway: the 1.1.0/1.2.0 evaluation terms dropped the rate from about
47,000 to about 32,000 nodes/second.

Engine by DeepSeek (deepseek-v4.1-flash).