Remove verbose output from rusqlite benchmark and output only CSV
format: system,threads,batch_size,compute,throughput
This makes it easier to parse and plot benchmark results.
Replace the sleep-based --think parameter with a --compute parameter
that uses a busy loop to simulate realistic CPU or GPU bound business
logic (e.g., parsing, data aggregation, or ML inference). The compute
time is now specified in microseconds instead of milliseconds for
finer granularity.
