feat: Implement MaxFailedTimes support and improve build configuration

[bamzest]

Changes:

• src/config/proxygroup.h: Add MaxFailedTimes field with default value 5
• src/config/binding.h: Update binding logic for MaxFailedTimes parsing
• src/handler/settings.cpp: Update settings handling for MaxFailedTimes
• base/pref.example.ini: Add MaxFailedTimes to example INI configuration
• base/pref.example.yml: Add MaxFailedTimes to example YAML configuration
• scripts/build.macos.release.sh: Use absolute paths for Python script execution
• .gitignore: Add base/subconverter to exclude compiled binary

This commit:

1. Completes the MaxFailedTimes feature implementation for proxy groups
2. Fixes compilation errors related to missing MaxFailedTimes member
3. Updates example configurations to demonstrate the new feature
4. Improves build script reliability by using absolute paths
5. Excludes compiled binaries from version control

The MaxFailedTimes field allows users to configure the maximum number of failed attempts before marking a proxy as unavailable, with a reasonable default value of 5.