Improve .NET SDK build infrastructure and documentation

- Add Central Package Management (Directory.Packages.props) with all package versions centralized
- Add Directory.Build.props with shared properties (TargetFramework, ImplicitUsings, Nullable, TreatWarningsAsErrors)
- Add nuget.config with single nuget.org source and package source mapping (required by CPM)
- Add global.json specifying .NET 10 SDK (the library is still built with a net8.0 TFM)
- Update all CI workflows from .NET 8.0.x to .NET 10.0.x
- Enable XML documentation file generation (GenerateDocumentationFile)
- Add XML doc comments to all non-generated public types and members
- Add valid-value lists in XML docs for string properties with known values (e.g. PermissionRequest.Kind, ToolResultObject.ResultType)
- Add #pragma warning disable CS1591 to generated files (SessionEvents.cs, Rpc.cs) and codegen scripts
- Enable EmbedUntrackedSources, IncludeSymbols, SymbolPackageFormat
- Enable ContinuousIntegrationBuild conditional on CI/TF_BUILD environment variables
- Add PackageProjectUrl to package metadata
- Add [EditorBrowsable(Never)] to obsolete GithubToken property
- Upgrade analysis level and fix some diagnostics

Author: stephentoub

.github/workflows/copilot-setup-steps.yml

@@ -58,7 +58,7 @@ jobs:
       - name: Set up .NET
         uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: "8.0.x"
+          dotnet-version: "10.0.x"
 
       # Install just command runner
       - name: Install just

.github/workflows/docs-validation.yml

@@ -108,7 +108,7 @@ jobs:
 
       - uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: "8.0.x"
+          dotnet-version: "10.0.x"
 
       - name: Install validation dependencies
         working-directory: scripts/docs-validation

.github/workflows/dotnet-sdk-tests.yml

@@ -43,7 +43,7 @@ jobs:
       - uses: actions/checkout@v6.0.2
       - uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: "8.0.x"
+          dotnet-version: "10.0.x"
       - uses: actions/setup-node@v6
         with:
           node-version: "22"

.github/workflows/publish.yml

@@ -121,7 +121,7 @@ jobs:
       - uses: actions/checkout@v6.0.2
       - uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: "8.0.x"
+          dotnet-version: "10.0.x"
       - name: Restore dependencies
         run: dotnet restore
       - name: Build and pack

.github/workflows/scenario-builds.yml

@@ -152,7 +152,7 @@ jobs:
 
       - uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: "8.0.x"
+          dotnet-version: "10.0.x"
 
       - uses: actions/cache@v4
         with:

.github/workflows/update-copilot-dependency.yml

@@ -38,7 +38,7 @@ jobs:
 
       - uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: "8.0.x"
+          dotnet-version: "10.0.x"
 
       - name: Update @github/copilot in nodejs
         env:

dotnet/Directory.Build.props

@@ -0,0 +1,12 @@
+<Project>
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <LangVersion>14</LangVersion>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <AnalysisLevel>10.0-minimum</AnalysisLevel>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+  </PropertyGroup>
+
+</Project>

dotnet/Directory.Packages.props

@@ -0,0 +1,19 @@
+<Project>
+
+  <PropertyGroup>
+    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageVersion Include="coverlet.collector" Version="6.0.4" />
+    <PackageVersion Include="Microsoft.Extensions.AI.Abstractions" Version="10.2.0" />
+    <PackageVersion Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.2" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
+    <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="10.0.102" />
+    <PackageVersion Include="StreamJsonRpc" Version="2.24.84" />
+    <PackageVersion Include="System.Text.Json" Version="10.0.2" />
+    <PackageVersion Include="xunit" Version="2.9.3" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
+  </ItemGroup>
+
+</Project>

dotnet/global.json

@@ -0,0 +1,6 @@
+{
+  "sdk": {
+    "version": "10.0.100",
+    "rollForward": "major"
+  }
+}

dotnet/nuget.config

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+  <packageSourceMapping>
+    <packageSource key="nuget.org">
+      <package pattern="*" />
+    </packageSource>
+  </packageSourceMapping>
+</configuration>