feat: document deployment patterns and host access implications

[dwmkerr]

Summary

Document the three deployment patterns for Shellwright, their security implications, and common use cases for each.

Deployment Patterns

1. stdio mode (default)

shellwright  # runs as MCP server over stdio

• Access: Full local filesystem, user permissions
• Risk: Shell commands run as the invoking user
• Use case: Local development, Claude Code integration

2. HTTP mode

shellwright --http --port 7498

• Access: Full access to the host system
• Risk: Centralized endpoint - multiple agents share one host
• Use case: Shared dev environments, CI/CD pipelines

3. Docker (isolated)

docker run -p 7498:7498 ghcr.io/dwmkerr/shellwright --http

• Access: Container filesystem only (no host access by default)
• Risk: Most isolated, but cannot access local files
• Use case: Sandboxed demos, untrusted workloads

Documentation Needed

1. README section - Quick overview of the three patterns
2. Security considerations - What each mode can/cannot access
3. Common use cases:
   • "I want to automate my local terminal" → stdio
   • "I want a shared shell server for my team" → HTTP + auth considerations
   • "I want to demo safely" → Docker
4. Mounting volumes in Docker - When you need specific paths available

Example Table for Docs

Pattern	Host Access	Isolation	Multi-agent	Setup
stdio	Full	None	No	Simple
HTTP	Full	None	Yes	Medium
Docker	None*	Container	Yes	Medium

*Unless volumes mounted