docs: Getting Started guide — zero to first session in 5 minutes

[OneStepAt4time]

M3.2 — Getting Started Guide

Parent: #440 (Roadmap)
Milestone: M3 — Reference Implementation
Depends on: #449 (examples exist to reference)

Content

1. Quick start — 5 commands from zero to working session:

   npm install -g aegis-bridge
   aegis-bridge start
   claude mcp add aegis -- npx aegis-bridge mcp
   # Now Claude Code can orchestrate sessions!

2. First session — create, send prompt, read result
3. Permission handling — what happens when CC asks for approval
4. Multiple sessions — parallel development
5. Dashboard — http://localhost:9100 overview
6. Troubleshooting FAQ — top 10 issues and fixes

Format

• docs/getting-started.md in repo
• Linked from README as primary entry point
• Optional: GIF/video demo (nice-to-have)

Acceptance criteria

• A developer who has never seen Aegis can get a working session in <5 minutes
• No assumed knowledge beyond Node.js and Claude Code installed