Resolve net task host params from the project properties

[YuliiaKovalova]

based on: #11393

fixes: #11343

This PR contains logic that helps to resolve NetTaskHost execution params based on the project properties.
DOTNET_HOST_PATH => resolves path to dotnet.exe
RuntimeIdentifierGraphPath => gives the path to the sdk version resolved for the given project.

The values are passed to NodeProviderOutOfProcTaskHost by using taskHostParameters.
The exception is generated on attempt to use this functionality for sdk9 and lower.

For further flexibility the packet versioning support was added in NodePacketType.

MSBuild Packet Structure Overview

MSBuild's packet communication protocol supports versioning through an extended header mechanism. This document outlines the binary structure of packets with and without version information.

Basic Packet Format

Position	Size (bytes)	Description
0	1	Packet Type Byte
1-4	4	Packet Length (32-bit integer)
5+	Variable	Packet Body

Packet Type Byte (Position 0) Bit Layout

Bits	Purpose
0-5	Base packet type (values 0-63)
6 (0x40)	Extended header flag - When set, indicates version information follows
7	Reserved for future use

NodePacketType Value Ranges

Range	Purpose	Examples
0x00-0x15	Core MSBuild packets (sequential)	NodeConfiguration, BuildRequest, LogMessage
0x16-0x3B	Reserved for future core packet expansion	(38 values available)
0x3C-0x3F	Server command packets	ServerNodeBuildCommand, ServerNodeBuildResult

Key Design Principle: Clean bit separation ensures the extended header flag (bit 6) never conflicts with packet type values (0-63).

Implementation Notes

• Bit field design: Lower 6 bits for packet type, bit 6 for extended header flag
• No conflicts: Packet type values (0-63) never set bit 6
• Server packet relocation: Moved from 0xF0-0xF3 to 0x3C-0x3F to avoid flag conflicts
• Extensible: 38 unused packet type slots + bit 7 reserved for future use

[baronfel]

Some very minor documentation nits as I was looking through. If I can understand this PR then you've done a great job making things easy to follow 🤣

[Copilot]

Pull Request Overview

This PR implements support for resolving NET Task Host execution parameters from project properties to address issues with task host initialization. The solution introduces packet versioning infrastructure to enable protocol compatibility and adds logic to extract dotnet host path and SDK version information from project properties.

• Adds packet versioning support with extended headers for MSBuild's communication protocol
• Implements logic to resolve DOTNET_HOST_PATH and RuntimeIdentifierGraphPath from project properties
• Refactors TaskHostConfiguration to use packet versioning instead of runtime parameters for AppDomain serialization decisions

Reviewed Changes

Copilot reviewed 22 out of 23 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/Shared/INodePacket.cs	Adds NodePacketTypeExtensions class with packet versioning utilities and reorganizes enum values
src/Shared/TaskHostConfiguration.cs	Removes runtime parameter dependency, uses packet version for AppDomain config decisions
src/Build/BackEnd/Components/Communications/NodeProviderOutOfProcTaskHost.cs	Implements project property resolution for NET runtime host paths and SDK validation
src/Build/BackEnd/Components/RequestBuilder/TaskBuilder.cs	Adds logic to gather dotnet host path and MSBuild assembly path from project properties
src/Shared/NodeEndpointOutOfProcBase.cs	Implements extended header reading and packet versioning in communication protocol
src/Framework/ITranslator.cs	Adds PacketVersion property to ITranslator interface
src/Framework/BinaryTranslator.cs	Implements PacketVersion property in both reader and writer translators
src/Build/BackEnd/Components/Communications/NodeProviderOutOfProcBase.cs	Implements extended header writing with packet versioning
src/Shared/CommunicationsUtilities.cs	Updates handshake logic to support predefined tools directory parameter
src/Build/Resources/Constants.cs	Adds constants for dotnet host path and MSBuild assembly path
src/Build/Instance/TaskFactories/TaskHostTask.cs	Updates constructor signature and method calls for new parameter handling
src/Build/Instance/TaskFactories/AssemblyTaskFactory.cs	Updates parameter merging logic and method signatures
src/Build/Evaluation/IntrinsicFunctions.cs	Updates method calls for new parameter handling
src/Build/Evaluation/Evaluator.cs	Updates SDK resolution to use new constant names
src/Shared/BuildEnvironmentHelper.cs	Removes unused NET-specific directory properties
src/Build/BackEnd/Node/OutOfProcServerNode.cs	Fixes typo in comment
src/Build/BackEnd/Components/Communications/NodeLauncher.cs	Updates comment for broader process types
src/UnitTests.Shared/RunnerUtilities.cs	Reorders field declarations
src/Build.UnitTests/TestAssets/ExampleNetTask/TestNetTask/TestNetTask.csproj	Adds SDK attribute to project
src/Build.UnitTests/NetTaskHost_E2E_Tests.cs	Updates test to use new environment variables and error handling
src/Build.UnitTests/BackEnd/TaskHostConfiguration_Tests.cs	Removes runtime parameter from test constructors
global.json	Reorders SDK paths priority

[rainersigwald]

Will look a the hard parts tomorrow 😅

[rainersigwald]

Overall looking good to me!