docs: add rider configuration documentation

docs/DeveloperGuide/EditorSetup/JetBrains Rider/index.md

@@ -0,0 +1,49 @@
+# JetBrains Rider setup with Unity
+
+## Install JetBrains Rider:
+
+- https://www.jetbrains.com/help/rider/Installation_guide.html#snap
+
+```bash
+sudo snap install rider --classic
+```
+
+## Install .NET SDK:
+
+- https://learn.microsoft.com/en-us/dotnet/core/install/linux-ubuntu#register-the-microsoft-package-repository
+
+```bash
+# Get Ubuntu version
+declare repo_version=$(if command -v lsb_release &> /dev/null; then lsb_release -r -s; else grep -oP '(?<=^VERSION_ID=).+' /etc/os-release | tr -d '"'; fi)
+
+# Download Microsoft signing key and repository
+wget https://packages.microsoft.com/config/ubuntu/$repo_version/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
+
+# Install Microsoft signing key and repository
+sudo dpkg -i packages-microsoft-prod.deb
+
+# Clean up
+rm packages-microsoft-prod.deb
+
+# Update packages
+sudo apt update
+sudo apt install dotnet-sdk-8.0
+```
+
+## Connect Rider to Unity Editor:
+
+- https://www.jetbrains.com/help/rider/Unity.html#8f092cb7_9
+
+```bash
+1) Open an existing Unity project in the Unity Editor.
+
+2) Select Edit | Preferences (Unity | Settings on macOS) and open the External Tools page.
+
+3) In the External Script Editor, select a $p1//product-profile[@id=$p2]/@name installation.
+
+4) In the Preferences window, click "Regenerate project files" under the External Tools section.
+
+5) While still in the Unity Editor, right-click anywhere in the Project view and select Open C# Project.
+
+6) Rider will start automatically and open the solution related to this Unity project. Once the solution is loaded, Rider and the Unity Editor become connected. The Unity icon on the toolbar shows the current connection status:
+```