Add comprehensive technical documentation for GhostJ refactoring

[Copilot]

Creates docs/技术文档.md (1,604 lines) to guide systematic refactoring of the GhostJ remote access platform.

Analysis Coverage

• Architecture: Three-tier Client/Server/Master system with custom text protocol
• Codebase metrics: 86 Java files, 8,869 LOC across 5 main packages
• Design patterns: Strategy pattern in client commands; identifies missing patterns (Factory, Observer, Chain of Responsibility)

Critical Issues Identified

Code quality (severity 🔴):

• 40+ static fields creating global state chaos (ServerMain has 22)
• 9 duplicate utility classes (Config/FileRW/Out × 3 copies each)
• 50+ improper exception handlers (swallowed exceptions, overly broad catches)
• Deprecated API usage: Thread.stop()

Security vulnerabilities:

• Plaintext communication (no TLS/SSL)
• Hardcoded password: masterPw="master123456"
• Command injection via Runtime.exec() with unsanitized network input
• Path traversal in file operations
• No connection limits (DoS vector)

Refactoring Roadmap

8-week plan structured in 4 phases:

1. Foundation (weeks 1-2): Consolidate duplicate classes, introduce SLF4J logging, fix exception handling
2. Architecture (weeks 3-4): Dependency injection to eliminate static fields, ExecutorService-based threading
3. Quality (weeks 5-6): TLS encryption, authentication framework, 60%+ test coverage
4. Polish (weeks 7-8): Performance tuning, API documentation

Documentation Structure

• Module deep-dives for Client/Server/Master/Util packages
• Before/after code examples for each refactoring step
• Dependency graphs and coupling analysis
• Configuration file specifications and protocol documentation
• Prioritized issue checklist with risk ratings

Original prompt

仔细阅读整个代码库 梳理结构和缺陷 写一个docs/技术文档，我们要进行重构

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.