Add Qt6 setup helpers and comprehensive build instructions

- Improved build.bat with auto-detection of Qt6 installation
  - Checks common Qt6 paths automatically
  - Provides helpful error messages with paths to check
  - Works with Qt6.4 through Qt6.8

- Added check-setup.bat verification script
  - Verifies CMake, Visual Studio 2022, and Qt6 installation
  - Reports found/missing prerequisites
  - Quick setup validation before building

- Added comprehensive SETUP.md documentation
  - Quick 3-step setup guide
  - Detailed manual setup instructions
  - Qt6 download and installation steps
  - Troubleshooting for common issues
  - Manual CMake command reference
  - Environment variable setup

- Updated README.md
  - Links to SETUP.md for first-time users
  - Quick build instructions
  - Clear prerequisites with download links
  - Better organized for both quick and manual builds

Fixes CMake Qt6 detection errors by:
1. Auto-searching common Qt6 installation paths
2. Providing fallback manual build instructions
3. Detecting missing prerequisites with helpful links

Co-authored-by: Cursor <cursoragent@cursor.com>

host-gui/build.bat

@@ -3,7 +3,7 @@ setlocal enabledelayedexpansion
 
 echo.
 echo ================================================================================
-echo  Commonwealth Online - Qt GUI Build Script
+echo  Commonwealth Online - Qt GUI Build Script (with Qt6 Auto-Detection)
 echo ================================================================================
 echo.
 
@@ -12,27 +12,83 @@ cmake --version >nul 2>&1
 if errorlevel 1 (
     echo ERROR: CMake is not installed or not in PATH.
     echo Please install CMake from https://cmake.org/download/
+    echo Then add it to your PATH and restart this script.
+    pause
+    exit /b 1
+)
+
+REM Auto-detect Qt6 installation
+echo Searching for Qt6 installation...
+set QT6_PATH=
+
+REM Common Qt6 installation paths (check in order)
+set PATHS_TO_CHECK[0]=C:\Qt\6.8.0\msvc2022_64
+set PATHS_TO_CHECK[1]=C:\Qt\6.7.0\msvc2022_64
+set PATHS_TO_CHECK[2]=C:\Qt\6.6.0\msvc2022_64
+set PATHS_TO_CHECK[3]=C:\Qt\6.5.0\msvc2022_64
+set PATHS_TO_CHECK[4]=C:\Qt\6.4.0\msvc2022_64
+set PATHS_TO_CHECK[5]=C:\Qt\6.8.0\msvc2019_64
+set PATHS_TO_CHECK[6]=C:\Qt\6.7.0\msvc2019_64
+set PATHS_TO_CHECK[7]=C:\Qt\6.6.0\msvc2019_64
+
+for /l %%i in (0,1,7) do (
+    if exist "!PATHS_TO_CHECK[%%i]!\lib\cmake\Qt6" (
+        set QT6_PATH=!PATHS_TO_CHECK[%%i]!
+        echo Found Qt6 at: !QT6_PATH!
+        goto found_qt6
+    )
+)
+
+:found_qt6
+if "!QT6_PATH!"=="" (
+    echo.
+    echo ERROR: Qt6 not found at common installation paths.
+    echo.
+    echo Please install Qt6 from https://www.qt.io/download-open-source
+    echo.
+    echo Common installation paths:
+    echo   - C:\Qt\6.8.0\msvc2022_64
+    echo   - C:\Qt\6.7.0\msvc2022_64
+    echo   - C:\Qt\6.6.0\msvc2022_64
+    echo.
+    echo Alternatively, manually set Qt6 path by editing this script
+    echo or run CMake manually with:
+    echo   cmake .. -G "Visual Studio 17 2022" -DCMAKE_PREFIX_PATH="C:\path\to\Qt6"
+    echo.
     pause
     exit /b 1
 )
 
 REM Create build directory
 if not exist "build" (
+    echo.
     echo Creating build directory...
     mkdir build
 )
 
 cd build
 
-echo Configuring Qt6 project with CMake...
-cmake .. -G "Visual Studio 17 2022" -DCMAKE_PREFIX_PATH="C:\Qt\6.4.0\msvc2019_64"
+echo.
+echo Configuring project with CMake...
+echo   CMake: %CMAKE_PREFIX_PATH%
+echo   Qt6:   !QT6_PATH!
+echo   VS:    Visual Studio 17 2022
+echo.
+
+cmake .. -G "Visual Studio 17 2022" -DCMAKE_PREFIX_PATH="!QT6_PATH!"
 
 if errorlevel 1 (
+    echo.
     echo ERROR: CMake configuration failed.
-    echo Make sure:
-    echo   1. Qt6 is installed
-    echo   2. Visual Studio 2022 is installed
-    echo   3. CMAKE_PREFIX_PATH points to your Qt6 installation
+    echo.
+    echo Troubleshooting:
+    echo   1. Verify Qt6 is installed at: !QT6_PATH!
+    echo   2. Verify Visual Studio 2022 is installed with C++ tools
+    echo   3. Try running this script again
+    echo.
+    echo Manual configuration command:
+    echo   cmake .. -G "Visual Studio 17 2022" -DCMAKE_PREFIX_PATH="!QT6_PATH!"
+    echo.
     pause
     exit /b 1
 )
@@ -40,11 +96,20 @@ if errorlevel 1 (
 echo.
 echo Configuration successful!
 echo.
-echo Building project...
+echo Building project (this may take a few minutes)...
+echo.
+
 cmake --build . --config Release
 
 if errorlevel 1 (
+    echo.
     echo ERROR: Build failed.
+    echo.
+    echo Troubleshooting:
+    echo   1. Check that Visual Studio 2022 is installed
+    echo   2. Make sure C++ development tools are installed
+    echo   3. Try building again
+    echo.
     pause
     exit /b 1
 )
@@ -54,6 +119,11 @@ echo ===========================================================================
 echo  Build successful!
 echo ================================================================================
 echo.
-echo Executable: %cd%\bin\Release\CommonwealthOnlineHost.exe
+echo Executable created at:
+echo   %cd%\bin\Release\CommonwealthOnlineHost.exe
+echo.
+echo To run the application:
+echo   cd ..
+echo   start build\bin\Release\CommonwealthOnlineHost.exe
 echo.
 pause