Add raid init --for-agent scaffold

[8bitAlex]

Scaffold a raid.yaml with verbose, well-commented examples optimized for AI coding agents to learn from via pattern-matching.

What it does

• Generates a fully-commented raid.yaml with every common field explained
• Includes CLAUDE.md, .cursor/rules/raid.mdc, and .github/copilot-instructions.md templates
• Templates teach the agent: what RAID is, how to read raid.yaml, common commands, safety semantics

Requirements

• New flag: raid init --for-agent
• Templates shipped as embedded assets in the binary
• Each template references the JSON Schema from Issue Add Claude Code GitHub Workflow #4

Acceptance criteria

• raid init --for-agent generates all scaffolding files
• Generated CLAUDE.md and Cursor rules verified to load without errors in Claude Code and Cursor on a fresh project
• README documents the flag and what it produces