This PR completes the C++23 modernization of ViewTouch and fixes a critical page inheritance bug introduced during refactoring.

Summary

• ✅ Complete C++23 Modernization: Converted all ~450+ snprintf/sprintf calls to std::format
• 🐛 Page Inheritance Fix: Restored parent page zone inheritance functionality
• 🔧 CI Updates: Updated CI workflow to use C++23 with GCC 14+
• 🛡️ Compiler Compatibility: Added feature detection for C++20/C++23 stdlib features

Changes

1. Complete C++23 Modernization (commit 9bc5f9c)

• Converted ~450+ snprintf/sprintf calls to C++23 std::format using format_to_buffer()
• Added cpp23_utils.hh library with format_to_buffer, to_underlying, Result<T>
• Modernized 60+ files across main, zone, src, term, loader, cdu
• Benefits: type safety, memory safety, readability, maintainability, zero runtime overhead
• All builds passing with 0 errors

2. Page Inheritance Fix (commit a1de375)

• Removed erroneous default: case in Page::Init() switch statement that forced parent_id = 0 for unhandled page types
• Restores inheritance for PAGE_SYSTEM, PAGE_TEMPLATE, PAGE_CHECKS, PAGE_KITCHEN_VID, PAGE_KITCHEN_VID2, PAGE_BAR1, PAGE_BAR2
• Matches master branch behavior where unhandled types retain initialized parent_id
• Fixes: Pages not showing inherited zones from parent pages

3. Compiler Compatibility (commit e425f05)

• Add __has_include detection for <format> and <expected> headers
• Provide fallback for std::to_underlying() using static_cast
• Conditionally compile std::expected types when available
• Add compile-time warning if std::format unavailable

4. CI Workflow Updates (commits 4df8de1, 50986cb, da44a86)

• Changed CI from C++20 to C++23 standard
• Restricted CI testing to GCC 14+ (only compiler with full C++23 stdlib support)
• Older compilers (GCC 12-13, Clang 16-18) lack std::format in libstdc++ even with -std=c++23
• Documents minimum compiler requirements in workflow

Testing

• ✅ Local builds passing (GCC 14.2.0, C++23)
• ✅ CI builds configured for GCC 14+ with C++23
• ✅ Page inheritance verified working correctly
• ✅ All 60+ modernized files compile successfully

Requirements

• C++23 compiler and standard library with std::format support
• GCC 14+ or equivalent (GCC 13 and Clang 18 lack complete C++23 stdlib)

Files Modified

• Core: cpp23_utils.hh (new), zone.cc
• Main: 31+ files in business/, data/, hardware/, ui/
• Zone: 18 zone implementation files
• CI: linux-simple-builds.yml
• Docs: changelog.md