Add cross-platform debugger detection implementation

[Kyle-Ye]

Summary

• Implement cross-platform debugger detection functionality based on SwiftUI's isDebuggerAttached
• Add Darwin-specific implementation using sysctl() with kinfo_proc and P_TRACED flag
• Add Linux implementation using /proc/self/status TracerPid field
• Include comprehensive test case to verify functionality

Implementation Details

Darwin (macOS/iOS)

• Uses sysctl() system call with KERN_PROC_PID to get process information
• Checks the P_TRACED flag in kp_proc.p_flag to detect debugger attachment
• Includes error handling with os_log for failed system calls

Linux

• Reads /proc/self/status file to get process status information
• Parses the TracerPid field - non-zero value indicates debugger attachment
• Gracefully handles file reading errors by returning false

Cross-platform Support

• Uses conditional compilation with #if canImport(Darwin) for platform-specific code
• Maintains consistent API across platforms with package let isDebuggerAttached: Bool
• Falls back to safe defaults (false) when detection fails

Test Coverage

• Added DebuggerTests.swift with test case ensuring isDebuggerAttached == false during normal execution
• Follows project testing conventions using swift-testing framework
• Test verifies both implementations work correctly in non-debugged environment

Compatibility

• Compatible with existing OpenSwiftUI build system and environment variables
• No breaking changes to public API
• Maintains SwiftUI API compatibility goals

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 24.45%. Comparing base (9a7abef) to head (c099fd4).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
Sources/OpenSwiftUICore/Util/Debugger.swift	85.71%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #509      +/-   ##
==========================================
+ Coverage   24.38%   24.45%   +0.07%     
==========================================
  Files         483      484       +1     
  Lines       27893    27921      +28     
==========================================
+ Hits         6802     6829      +27     
- Misses      21091    21092       +1     

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