Add structured log output with timestamps

Replace plain eprintln! messages with timestamped log format matching
satellome conventions: "YYYY-MM-DD HH:MM:SS - arraysplitter - INFO - ..."
Also track total input basepairs and show output file list.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ad3002

src/rust/arraysplitter/Cargo.lock

@@ -37,6 +37,9 @@ statrs = "0.16"
 # System info (memory, CPU)
 sysinfo = "0.30"
 
+# Date/time for logging
+chrono = "0.4"
+
 [[bin]]
 name = "arraysplitter"
 path = "src/main.rs"