Add initial support for creating and hosting MCP Tools; Add initial support for creating JSON Schema definitions

[Badgerati]

Description of the Change

This adds initial support for creating and host MCP Tools in Pode, as well as utility functions for creating JSON Schema definitions - similar to the existing OpenAPI support.

The MCP Tool support is in the early stages, so could change overtime as further MCP Servers are tested.

Current support for MCP:

• Hosting a Route to parse requests from MCP Servers - initialize, tools/list, and tools/call
• Creating MCP Tools via ScriptBlocks - both parameterless and with parameters
• Assigning Tools into Groups, allowing different Routes to manage different Tools
• Ability to add parameter definitions via JSON Schema - both manually and automatically
• JSON RPC error code support for servers

Current JSON Schema support:

• Types supported: null, string, integer, number, boolean, array, object
• Property support for objects - to define a name/required for a schema
• Support for merging schemas into allOf, anyOf, oneOf, and not.
• (re-usable references currently not implemented)

Examples

Creates and hosts an MCP Tool at http://localhost:8080/mcp, which allows you to ask a connected MCP server Get me all services running on this machine

Start-PodeServer -Threads 2 {
    Add-PodeEndpoint -Address localhost -Port 8080 -Protocol Http

    # Create a simple default group for MCP tools
    Add-PodeMcpGroup -Name 'Default' -Description 'Default group for MCP tools'

    # Add a simple MCP tool for returning windows services names for a given state
    Add-PodeMcpTool -Name 'GetWindowsServicesByState' -Description 'Returns Windows service names for a given state' -Group 'Default' -ScriptBlock {
        param(
            [ValidateSet('Running', 'Stopped', 'Paused')]
            [string]
            $State
        )

        $services = Get-Service -ErrorAction Ignore | Where-Object { $_.Status -ieq $State } | Select-Object Name
        if (($null -eq $services) -or (Test-PodeIsEmpty $services)) {
            $services = "No services found in the '$State' state."
        }

        return New-PodeMcpTextContent -Value $services
    } -PassThru |
        Add-PodeMcpToolProperty -Name 'State' -Required -Definition (
            New-PodeJsonSchemaString -Description 'The state of services to check' -Enum 'Running', 'Stopped', 'Paused'
        )

    # Add the MCP route
    Add-PodeRoute -Method Post -Path '/mcp' -ScriptBlock {
        Resolve-PodeMcpRequest -Group 'Default'
    }
}