setup: fix macOS thread count using hw.logicalcpu instead of hw.ncpu

[Divinesoumyadip]

Fixes #4028

Currently, etc/DependencyInstaller.sh uses sysctl -n hw.ncpu to determine the thread count on macOS. However, hw.ncpu only returns the number of physical cores. This ends up underestimating the available parallelism, particularly on Intel Macs that utilize hyperthreading.

This PR replaces hw.ncpu with hw.logicalcpu. hw.logicalcpu correctly returns all logical cores (including hyperthreaded ones), making it the exact macOS equivalent to the nproc command on Linux.

• On an Intel Mac with 4 physical cores and hyperthreading, hw.ncpu returns 4, while hw.logicalcpu correctly returns 8.
• On Apple Silicon (e.g., an M2 with 10 cores), both commands return 10.

This swap ensures we are fully utilizing the available CPU resources to speed up dependency installation on macOS.

[Divinesoumyadip]

@maliberty @luarss could you approve the workflows to run CI? Happy to address any review feedback.