Simulator debug design

Context

The docs need an embedded simulator panel so developers can paste map payloads and validate rendering without leaving VitePress.

Scope

• Add a new top-level docs section: simulator.
• Build a lightweight playground component with a clean UI.
• Support mapHex (required), pathHex (optional), and roomProperties JSON (optional).

Design choices

1. Keep implementation independent from src/app/debugTools.
2. Use a browser-only VitePress component and wrap it with ClientOnly.
3. Determine map type from input prefix:
   • 7b22: structured map
   • otherwise: raster map
4. Default sample input uses only mapHex from existing mock data.
5. Provide full-screen editing for long payloads.

UX

• Two-column layout on desktop, stacked layout on mobile.
• Explicit render action instead of auto-render while typing.
• Inline status and error messages with field-level failure context.

Verification

• New nav item 模拟调试 appears next to 参考.
• /simulator/ renders and can draw map from default sample.
• Optional inputs can be empty without blocking map rendering.