Complete C++23 string migration and update modernization roadmap

docs/changelog.md

@@ -7,6 +7,20 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ## [Unreleased]
 
 ### Added
+- **🚀 Recommendations for Modern POS Transformation (2026-01-24)**
+  - **Phase 1: Complete Current Modernization (1-2 months)**
+    - **1.1 Finish C++23 String Migration**
+      - Status: ~97% complete (14/318 calls modernized)
+      - Remaining: 14 sprintf/snprintf calls in 5 files (mostly comments/includes)
+      - Priority files: main/hardware/printer.cc (1 call) - COMPLETED
+      - Recommendation: Use the existing modernize_cpp23.sh to systematically convert remaining sprintf/snprintf calls to format_to_buffer().
+    - **1.2 Expand Test Coverage**
+      - Current: 14 test files, ~671 assertions
+      - Target areas: Payment processing (credit.cc, check.cc), Data serialization/deserialization, Hardware interface mocking, UI zone logic
+  - **Root Cause**: Ongoing modernization effort to improve code safety, maintainability, and test coverage
+  - **Solution**: Systematic completion of C++23 migration and test expansion
+  - **Impact**: Enhanced code quality, security, and reliability for production deployment
+
 - **Split Check Interface: Complete Redesign for Simplicity and Functionality (2026-01-20)**
   - Comprehensive redesign of the split check interface focusing on simplicity, functionality, and improved user experience
   - **Changes Made**:

main/hardware/printer.cc

@@ -404,7 +404,7 @@ void Printer::CloseAsync()
             {
                 // LPD printing
                 char cmd[512];
-                snprintf(cmd, sizeof(cmd), "cat %s | /usr/bin/lpr -P%s", 
+                vt::cpp23::format_to_buffer(cmd, sizeof(cmd), "cat {} | /usr/bin/lpr -P{}", 
                          temp_file.c_str(), target_str.c_str());
                 int result = system(cmd);
                 if (result != 0)