Expand description
UUID generation — small, no uuid crate dep.
(uuid-v4) → “550e8400-e29b-41d4-a716-446655440000”
Uses the OS RNG via /dev/urandom on Unix or getrandom syscall on
recent Linux. Falls back to std::time::SystemTime-derived nonce
plus a counter on systems where neither is available — sufficient
for log correlation IDs but not cryptographically secure on those
platforms; the implementation prefers the OS RNG everywhere it can.