[ BOUNTY] [Python] Add cross-platform health check fallbacks

[Xiaofei-Z]

Summary

Adds cross-platform fallbacks for check_memory_usage() and check_load_average() so non-Linux environments report useful values instead of generic /proc read failures.

Changes

• tools/health_check.py:
  • check_memory_usage(): /proc/meminfo on Linux → vm_stat+sysctl on macOS → psutil as generic fallback
  • check_load_average(): /proc/loadavg on Linux → os.getloadavg() on Unix → psutil on Windows
• tests/test_cross_platform_health.py: 10 tests covering Linux path simulation, fallback paths, missing /proc simulation, macOS behavior

Testing

Fallback behavior:

• Linux: /proc/meminfo and /proc/loadavg (unchanged, backward compatible)
• macOS: vm_stat + sysctl hw.memsize for memory; os.getloadavg() for load
• Other/Windows: psutil if available, otherwise graceful WARNING

Test coverage:

• Memory returns valid tuple on any platform
• Load returns valid tuple on any platform
• Status always in (OK, WARNING, CRITICAL)
• Non-Linux fallback does not crash
• Linux path simulated with mock /proc files
• Missing /proc files produce WARNING with error detail
• 10/10 tests pass

python3 tests/test_cross_platform_health.py

Build validation:

python3 build.py

Diagnostic artifacts: diagnostic/build-9659efd1-part001..004.logd + diagnostic/build-9659efd1-metadata.json

Diagnostic password: cbc7af3146d522ee68f0

Checklist

• Relevant modules affected by these changes build locally
• Tests pass locally
• Diagnostic build log is committed in this PR
• Documentation has been updated (fallback behavior documented in function docstrings)
• Configuration or schema changes are documented, if applicable
• No generated build artifacts are committed, except the required diagnostic build log
• Changes are scoped to the PR purpose and avoid unrelated cleanup
• Security, privacy, and error-handling implications have been considered

[Xiaofei-Z]

Hi @weilixiong, submitted this for bounty #1. Adds cross-platform fallbacks: /proc/meminfo on Linux, vm_stat on macOS, psutil generic for memory; /proc/loadavg on Linux, os.getloadavg() on Unix, psutil on Windows for load average. 10 tests pass, build diagnostics included. Happy to address feedback!