add sample python connector with pythonnet

Sample.PythonConnector/.gitignore

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+# Local configuration with credentials - do not commit
+config.yml
+
+# State database
+state.db
+
+# Python cache
+__pycache__/
+*.pyc
+
+bin
+obj
+
+publish/
+files/

Sample.PythonConnector/ConnectorRuntime.cs

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+using Cognite.Simulator.Utils;
+using Cognite.Simulator.Utils.Automation;
+using CogniteSdk.Alpha;
+using Microsoft.Extensions.DependencyInjection;
+using Sample.PythonConnector.Lib;
+
+namespace Sample.PythonConnector;
+
+public static class ConnectorRuntime
+{
+    public static void Init()
+    {
+        DefaultConnectorRuntime<PythonConfig, DefaultModelFilestate, DefaultModelFileStatePoco>
+            .ConfigureServices = ConfigureServices;
+        DefaultConnectorRuntime<PythonConfig, DefaultModelFilestate, DefaultModelFileStatePoco>
+            .ConnectorName = "MuJoCo";
+        DefaultConnectorRuntime<PythonConfig, DefaultModelFilestate, DefaultModelFileStatePoco>
+            .SimulatorDefinition = PythonSimulatorDefinitionBridge.Get();
+    }
+
+    static void ConfigureServices(IServiceCollection services)
+    {
+        services.AddScoped<ISimulatorClient<DefaultModelFilestate, SimulatorRoutineRevision>, 
+            PythonBridgeClient>();
+    }
+
+    public static async Task RunStandalone()
+    {
+        Init();
+        await DefaultConnectorRuntime<PythonConfig, DefaultModelFilestate, DefaultModelFileStatePoco>
+            .RunStandalone().ConfigureAwait(false);
+    }
+}

Sample.PythonConnector/Program.cs

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+namespace Sample.PythonConnector;
+
+public class Program
+{
+    public static int Main(string[] args)
+    {
+        try
+        {
+            ConnectorRuntime.RunStandalone().Wait();
+            return 0;
+        }
+        catch (Exception ex)
+        {
+            Console.Error.WriteLine($"Fatal error: {ex.Message}");
+            if (ex.InnerException != null)
+            {
+                Console.Error.WriteLine($"Inner exception: {ex.InnerException.Message}");
+            }
+            return 1;
+        }
+    }
+}

Sample.PythonConnector/README.md

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+# MuJoCo Python Connector
+
+A sample connector using pythonnet to integrate [MuJoCo](https://mujoco.org/) physics simulator with CDF. Python files are embedded in the executable at build time.
+
+## Architecture
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│                    .NET Connector Runtime                   │
+├─────────────────────────────────────────────────────────────┤
+│                    lib/ (C# Bridge Layer)                   │
+├─────────────────────────────────────────────────────────────┤
+│  EmbeddedPythonLoader   │  Extracts .py files, auto-detect  │
+│  PythonBridgeBase       │  GIL handling, large-stack exec   │
+│  PythonBridgeClient     │  ISimulatorClient implementation  │
+│  PythonBridgeRoutine    │  IRoutineImplementation impl      │
+├─────────────────────────────────────────────────────────────┤
+│                  python/ (Embedded at build)                │
+├─────────────────────────────────────────────────────────────┤
+│  definition.py          │  Simulator definition (MuJoCo)    │
+│  client.py              │  MuJoCo model loading/validation  │
+│  routine.py             │  Simulation execution engine      │
+└─────────────────────────────────────────────────────────────┘
+```
+
+## Prerequisites
+
+- .NET 8.0 SDK
+- Python 3.9+ with: `pip install mujoco find-libpython`
+
+## Production Build
+
+```bash
+# macOS Apple Silicon
+dotnet publish -c Release -r osx-arm64 --self-contained \
+  -p:PublishSingleFile=true \
+  -p:IncludeNativeLibrariesForSelfExtract=true \
+  -p:DebugType=none -o ./publish
+
+# Linux x64
+dotnet publish -c Release -r linux-x64 --self-contained \
+  -p:PublishSingleFile=true \
+  -p:IncludeNativeLibrariesForSelfExtract=true \
+  -p:DebugType=none -o ./publish
+
+# Windows x64
+dotnet publish -c Release -r win-x64 --self-contained \
+  -p:PublishSingleFile=true \
+  -p:IncludeNativeLibrariesForSelfExtract=true \
+  -p:DebugType=none -o ./publish
+```
+
+Produces a single ~85MB executable with embedded Python files.

Sample.PythonConnector/Sample.PythonConnector.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <LangVersion>12.0</LangVersion>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Cognite.Simulator.Utils\Cognite.Simulator.Utils.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="pythonnet" Version="3.0.4" />
+  </ItemGroup>
+
+  <!-- Embed Python files as resources at build time -->
+  <ItemGroup>
+    <EmbeddedResource Include="python\*.py">
+      <LogicalName>%(Filename)%(Extension)</LogicalName>
+    </EmbeddedResource>
+  </ItemGroup>
+
+</Project>

Sample.PythonConnector/config.example.yml

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+version: 1
+
+logger:
+    console:
+        level: "debug"
+
+cognite:
+    project: ${COGNITE_PROJECT}
+    host: ${COGNITE_HOST}
+    idp-authentication:
+        tenant: ${COGNITE_TENANT_ID}
+        client-id: ${COGNITE_CLIENT_ID}
+        secret: ${COGNITE_CLIENT_SECRET}
+        # scopes:
+        #   - https://api.cognitedata.com/.default
+        scopes:
+          - ${COGNITE_SCOPE}
+
+connector:
+  name-prefix: "mujoco-connector@"
+  data-set-id: ${COGNITE_DATA_SET_ID}
+
+# MuJoCo Connector Configuration
+# =================================
+# This connector integrates MuJoCo physics simulator with Cognite Data Fusion.
+# Python files (definition.py, client.py, routine.py) are embedded in the executable
+# at build time - no external Python files needed on the target machine.
+#
+# Supported model file types: .xml (MJCF), .mjcf, .urdf
+#
+automation:
+  # Path to Python DLL (optional, pythonnet will auto-detect if not specified)
+  # On Windows: "python311.dll" or "C:\\Python311\\python311.dll"
+  # On Linux: "libpython3.11.so" or "/usr/lib/x86_64-linux-gnu/libpython3.11.so"
+  # On macOS: "libpython3.11.dylib" or "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.11/lib/libpython3.11.dylib"
+  # python-dll: ""
+
+  # Python home directory (optional, for setting PYTHONHOME)
+  # python-home: ""
+
+  # Timeout for Python operations in milliseconds (5 minutes)
+  execution-timeout: 300000
+
+  # Additional Python paths to add to sys.path (optional)
+  # NOTE: MuJoCo must be installed in the Python environment: pip install mujoco
+  # python-paths:
+  #   - "/path/to/additional/modules"