Updates build instructions for Linux and Windows

Clarifies the build process for both Linux and Windows environments, including specific instructions for Visual Studio 2022.

This includes updated prerequisites, build commands, and testing procedures, ensuring a smoother build experience for developers on both platforms.

CLAUDE.md

@@ -4,15 +4,17 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ## Build System
 
-ResInsight uses CMake with Ninja as the build generator. The project requires:
+ResInsight uses CMake with multiple build generators supported. The project requires:
 - CMake 3.26+ (boost dependency requirement)
 - C++23 standard
-- GCC 13+ or Clang 19+
+- GCC 13+ or Clang 19+ (Linux) / MSVC 2022 17.8+ (Windows)
 - Python 3.8+
 - Qt 6.4+
 
 ### Prerequisites and Dependencies
 
+#### Linux (Ubuntu/Debian)
+
 ```bash
 # Update system and install build tools
 sudo apt update
@@ -30,8 +32,28 @@ git submodule update --init
 ThirdParty/vcpkg/bootstrap-vcpkg.sh
 ```
 
+#### Windows (Visual Studio 2022)
+
+```powershell
+# Install prerequisites:
+# - Visual Studio 2022 (17.8+) with C++ workload and CMake tools
+# - Qt 6.4+ (via Qt Online Installer or vcpkg)
+# - Git for Windows
+# - Python 3.8+
+
+# Clone repository and initialize submodules
+git clone https://github.com/OPM/ResInsight
+cd ResInsight
+git submodule update --init
+
+# Bootstrap vcpkg for dependency management
+ThirdParty\vcpkg\bootstrap-vcpkg.bat
+```
+
 ### Build Commands
 
+#### Linux
+
 ```bash
 # Configure with CMake preset (recommended)
 cmake . --preset=linux-base
@@ -51,14 +73,40 @@ ninja -C build ResInsight
 ninja -C build extract-projectfile-versions
 ```
 
+#### Windows (Visual Studio 2022)
+
+```powershell
+# Configure with CMake preset (recommended)
+cmake . --preset=x64-relwithdebinfo
+# Note: Copy CMakeUserPresets-example-windows.json to CMakeUserPresets.json and update Qt paths
+
+# OR using Visual Studio 2022 CMake integration:
+# 1. Open Visual Studio 2022
+# 2. File -> Open -> Folder -> Select ResInsight root directory
+# 3. VS will automatically detect CMakeLists.txt and configure the project
+# 4. Select x64-relwithdebinfo configuration from the dropdown
+# 5. Build -> Build All
+
+# Build the project from command line
+cmake --build --preset x64-relwithdebinfo
+
+# Build specific targets
+cmake --build --preset x64-relwithdebinfo --target ResInsight
+cmake --build --preset x64-relwithdebinfo --target extract-projectfile-versions
+```
+
 ### Build Presets
 
 Available CMake presets in `CMakePresets.json`:
 - `ninja`: Base configuration with vcpkg toolchain, unit tests enabled, warnings as errors
-- `linux-base`: Inherits from ninja, includes Qt path configuration
+- `linux-base`: Inherits from ninja, includes Qt path configuration (Linux)
 - `x64-release`: Release build configuration
+- `x64-relwithdebinfo`: Release with debug info configuration (Windows)
+- `x64-debug`: Debug build configuration (Windows)
 
-Create `CMakeUserPresets.json` from example file and update `CMAKE_PREFIX_PATH` for Qt installation.
+Create `CMakeUserPresets.json` from appropriate example file:
+- Linux: Copy `CMakeUserPresets-example-linux.json` and update `CMAKE_PREFIX_PATH` for Qt installation
+- Windows: Copy `CMakeUserPresets-example-windows.json` and update Qt paths, Python executable, and ODB API paths
 
 ### Code Style and Formatting
 
@@ -70,6 +118,8 @@ Use clang-format-19 to enforce style.
 
 The project uses CTest for testing:
 
+#### Linux
+
 ```bash
 # From build directory
 ctest
@@ -83,6 +133,21 @@ ctest -R "roffcpp-tests"
 ctest -R "regression-analysis-tests"
 ```
 
+#### Windows
+
+```powershell
+# From build directory
+ctest -C RelWithDebInfo
+# OR using CMake preset
+cmake --build --preset x64-relwithdebinfo --target test
+
+# Run specific test suites
+ctest -R "UnitTests" -C RelWithDebInfo
+ctest -R "opm-parser-tests" -C RelWithDebInfo
+ctest -R "roffcpp-tests" -C RelWithDebInfo
+ctest -R "regression-analysis-tests" -C RelWithDebInfo
+```
+
 ## Architecture Overview
 
 ResInsight is a 3D visualization and post-processing tool for reservoir simulation data built with a modular architecture:
@@ -131,6 +196,8 @@ ResInsight includes Python integration via gRPC when `RESINSIGHT_ENABLE_GRPC=ON`
 
 ### Python tests
 
+#### Linux
+
 ```bash
 # Make a virtual environment: 
 python3 -m venv venv-claude
@@ -143,7 +210,24 @@ pip install pytest
 
 # Run the tests (e.g all tests in tests_polygons.py):
 cd GrpcInterface/Python/rips && source /workspace/venv-claude/bin/activate && RESINSIGHT_EXECUTABLE=build-claude/ResInsight python -m pytest tests/test_polygons.py --console
+```
 
+#### Windows
+
+```powershell
+# Make a virtual environment: 
+python -m venv venv-claude
+
+# Start the virtual env:
+venv-claude\Scripts\Activate.ps1
+
+# Install pytest
+pip install pytest
+
+# Run the tests (e.g all tests in tests_polygons.py):
+cd GrpcInterface\Python\rips
+$env:RESINSIGHT_EXECUTABLE="..\..\..\..\build\RelWithDebInfo\ResInsight.exe"
+python -m pytest tests/test_polygons.py --console
 ```
 
 ### Python formatting and code style checks using ruff