refactor(mcp): add NewServerFrom constructor for dependency injection (for module extensibility)

[mfaizanse]

Summary

This PR refactors the MCP server construction to support dependency injection, enabling external Go modules to customize the server when using kubernetes-mcp-server as a module dependency.

Changes

New Constructor: NewServerFrom

Added a new exported constructor that accepts pre-configured components:

func NewServerFrom(
    configuration Configuration,
    mcpServer *mcp.Server,
    targetProvider internalk8s.Provider,
    metrics *metrics.Metrics,
) (*Server, error)

Use Cases

External packages can now:

• Provide a custom mcp.Server with different options or additional middleware.
• Inject custom metrics implementations.
• Control middleware order and composition. For example, passing custom metadata from ToolsParams to the Provider etc.
• Reuse core server logic with different configurations

Example usage

import "github.com/containers/kubernetes-mcp-server/pkg/mcp"

// Create custom MCP server with your middleware
mcpServer := mcp.NewServer(impl, opts)
mcpServer.AddReceivingMiddleware(myCustomMiddleware)

// Use NewServerFrom with your custom components
mcpServer, err := mcp.NewServerFrom(config, mcpServer, provider, myMetrics)

if m.StaticConfig.Port != "" {
    ctx := context.Background()
    return internalhttp.Serve(ctx, mcpServer, m.StaticConfig, oidcProvider, httpClient)
}

[matzew]

Hey 👋

thanks for the PR, mind to update it ?

[mfaizanse]

Hey 👋

thanks for the PR, mind to update it ?

@matzew I have resolved the merge conflicts.