[MAINTENANCE] Refactor mainTrafficLayer.cpp for improved code quality and maintainability

[yunlishao]

Task Summary
Comprehensive refactoring of mainTrafficLayer.cpp to improve code quality, reduce technical debt, and enhance maintainability. This includes cleaning up printout/banner messages, removing dead/commented code, consolidating duplicate logic, improving code structure, and implementing memory safety improvements.

Why is this needed?
The current mainTrafficLayer.cpp has grown to ~950 lines with accumulated technical debt:

• Inconsistent and scattered console output during startup
• Dead code and TODO comments that should be tracked issues
• Duplicated logic patterns that increase maintenance burden
• Large monolithic main() function that's difficult to navigate
• Unsafe memory patterns (volatile vs atomic, raw file handles)

Refactoring will improve code readability, reduce bugs, and make future development more efficient.

Scope of Work
Files involved:

• TrafficLayer/TrafficLayer/mainTrafficLayer.cpp

Tasks:

1. Printout/Banner Cleanup

• Remove extra \n\n formatting inconsistencies (completed in initial cleanup)
• Remove "No verbose logging" negative info print (completed)
• Consolidate scattered port prints into single summary (completed)
• Add build date/time to banner (__DATE__, __TIME__)
• Add configuration summary block after config parsing

2. Remove Dead/Commented Code

• Remove old TODO comments (lines 132-141) - convert to tracked issues
• Remove unnecessary file existence check (lines 359-366)
• Remove empty debug blocks (int aa = 1; at lines 924-925, 1145)
• Remove empty verbose block (lines 481-486)
• Remove large commented-out code blocks (lines 623-641)

3. Consolidate Duplicate Logic

• Extract subscription handling to helper function (lines 488-523 duplicate pattern)
• Create extractPortsFromSubscription() function (lines 537-584 repeated pattern)
• Consolidate identical sendData branches (lines 1002-1036)

4. Improve Code Structure

• Extract functions from main():
  • parseCommandLineArgs()
  • initializeLogging()
  • setupConfiguration()
  • setupConnections()
  • runSimulationLoop()
• Move Timer_t struct closer to usage or remove if ENABLE_TIMING always false
• Move global variables Config_c, Sock_c into main or pass as parameters

5. Memory/Resource Safety Improvements

• Replace volatile bool with std::atomic<bool> for g_shutdown.shutdownRequested (line 17)
• Use RAII for file handles - replace fopen/fclose pairs with std::ofstream

6. Configuration Cleanup

• Remove ENABLE_TIMING code if hardcoded to false, or make configurable via config.yaml

Environment (if version-specific)

• C++ compiler/version: Visual Studio 2022

Risks or Dependencies

• Changes to main executable require thorough testing across all simulator combinations (VISSIM/SUMO, with/without CarMaker, with/without Carla)
• Should be done incrementally with testing between each major change
• No external dependencies

Additional Context (optional)
This issue was created after initial cleanup of startup printout formatting. The initial cleanup normalized console output formatting and consolidated scattered port information into a single summary line.

Related line references are based on the current state after initial cleanup and may shift as changes are made.

[yunlishao]

Expected Startup Printout Format

After refactoring, the startup output should look like this:

==================================================
        Real-Sim TrafficLayer v0.7.0
              (RELEASE build)
==================================================

Configuration: config.yaml
Traffic Simulator: SUMO
Traffic Simulator Server: 127.0.0.1:1337

Waiting for clients to connect...
  Client #1 connected (127.0.0.1:2444)
  Client #2 connected (127.0.0.1:2555)
All clients connected

Initializing SUMO...
  Config: simple_loop.sumocfg
  Mode: SUMO-GUI (auto-launch)
Connected to SUMO successfully

Simulation started
===========SimTime 0.000000==============

Key Requirements

1. Default messages suppressed - Added SuppressDefaultMessages flag to ConfigHelper (completed)
2. Group connection info - Server and client IPs/ports are prominent and easy to find
3. Client format - Show Client #N connected (IP:Port) for each client
4. Reduce noise - Remove redundant confirmations

Files to Modify

• CommonLib/SocketHelper.cpp - Update client connection messages to include port in format Client #N connected (IP:Port)
• TrafficLayer/TrafficLayer/mainTrafficLayer.cpp - Add Traffic Simulator Server: IP:Port line after traffic simulator selection