feat: add in-process C# MCP server, Kestrel HTTP API, and AI skill

[doomedraven]

Summary

This PR completes our integration suite by introducing native Model Context Protocol (MCP) server capabilities to de4dotEx over standard IO, alongside a lightweight, containerized HTTP Web API and a dedicated AI Skill for LLM agents.

This connects de4dotEx directly to your AI development environment (Claude Desktop, Cursor, etc.).

Key Changes

1. Native C# Stdio/HTTP MCP Server (de4dot.mcp):

   • Creates a new .NET 8.0 project de4dot.mcp inside the cross-platform solution.
   • Implements the official MCP JSON-RPC protocol over standard input/output (stdin/stdout), exposing the deobfuscate tool (accepts file_path, output_path, and custom native deobfuscation options).
   • Integrates an in-process Kestrel HTTP Web API on port 8080 (invoked via --http flag) that accepts multipart/form-data uploads (file and optional native CLI options fields), processes them safely, and returns the cleaned binary directly in the HTTP body response.
   • Restructures console logging to redirect all native de4dot output to an in-memory buffer, preventing stdout pollution during JSON-RPC exchanges.

2. Unified Docker Integration:

   • Restores Dockerfile to build and package both de4dot and de4dot.mcp binaries side-by-side, exposing port 8080.
   • Integrates an intelligent routing entrypoint script entrypoint.sh inside the container:
     • Default command executes the standard de4dot CLI utility.
     • --mcp runs the Stdio MCP server background process.
     • --mcp --http starts the containerized Kestrel HTTP REST microservice.

3. Gemini CLI Skill (dotnet-deobfuscate/):

   • Packages a specialized AI dotnet-deobfuscate skill (SKILL.md) that injects expert-level triage instructions, parameters, and Detect It Easy (DiE) signature-to-de4dot-flag mappings directly into LLM agent contexts.

4. Testing Client & Documentation:

   • Adds the test_api.sh client utility script to quickly upload and download cleaned files next to original directories with _cleaned suffixes.
   • Integrates complete MCP server build, configuration (Claude Desktop & Cursor IDE), and runtime usage guides directly into the primary README.md.