Add NuGet packaging for PythonNet3 engine

Introduced a nuspec file and nuget.config for packaging DynamoVisualProgramming.PythonEngine.PythonNet3. Updated pipeline.yml to support NuGet deployment using a secret API key and new configuration files.

Author: zeusongit

DynamoVisualProgramming.PythonEngine.PythonNet3.nuspec

@@ -0,0 +1,19 @@
+<?xml version="1.0"?>
+<package xmlns="http://schemas.microsoft.com/packaging/2012/06/nuspec.xsd">
+    <metadata>
+        <id>DynamoVisualProgramming.PythonEngine.PythonNet3</id>
+        <version>0.0.0</version>
+        <authors>Autodesk</authors>
+        <owners>Autodesk</owners>
+        <license type="expression">Apache-2.0</license>
+        <projectUrl>https://github.com/DynamoDS/PythonNet3Engine</projectUrl>
+        <requireLicenseAcceptance>false</requireLicenseAcceptance>
+        <description>PythonNet3 Engine Nuget, it contains the necessary binaries to load the PythonNet3 engine to Dynamo</description>
+        <copyright>Copyright Autodesk 2025</copyright>
+    </metadata>
+    <files>
+        <file src="package_output\pkg.json" target="" />
+        <file src="package_output\bin\**" target="bin\" exclude="bin\DSPythonNet3*.pdb;" />
+        <file src="package_output\extra\**" target="extra\" />
+    </files>
+</package>

nuget.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <add key="Public Nuget" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+</configuration>

pipeline.yml

@@ -7,6 +7,12 @@ env:
   - SLACK_QUANTUM_BUILD_CHANNEL : "#dynamo-jenkinsbuild"
   - JENKINS_NODE_WIN: CDA-VS22-SVC
 
+jenkins_creds:
+  -
+    type: secretText
+    credentialsId: dynamovisualprogramming_nuget_api_key
+    secretText: API_KEY
+
 code_analysis:
   sonarqube:
     source_encoding: UTF-8
@@ -44,3 +50,11 @@ deployment:
     use_dev_pm: false
     outputs:
       - DSPythonNet3.zip
+  -
+    type: nuget
+    custom_api_key: ${API_KEY}
+    nuget_config_file: nuget.config
+    nuspec_files:
+      - DynamoVisualProgramming.PythonEngine.PythonNet3.nuspec
+    package_version_cmd: echo %MS_PACKAGE_VERSION%
+    destination_source_name: Public Nuget