feat: add material creation, preview, live coding, and editor exit tools

[steakbbq]

Summary

New MCP tools for material authoring workflow and editor control:

• material_create: Create materials with Custom HLSL nodes programmatically - add parameters, wire connections, set shader code all via MCP
• material_preview: Capture material preview thumbnail as base64 JPEG for visual feedback
• live_coding: Trigger hot reload compilation (equivalent to Ctrl+Alt+F11)
• editor_exit: Gracefully close the editor with save dialog for unsaved changes

Enhanced get_material_info in the existing material tool:

• Shows blend mode, shading model, two-sided status
• Shows parameter nodes with names, types, and default values
• Shows Custom HLSL nodes with code length, inputs, and connections

Also adds MaterialEditor module dependency for material graph manipulation.

Test plan

• Create a new material via material_create with create_material operation
• Add scalar/vector parameters via add_parameter
• Add Custom HLSL node via add_custom_node
• Wire parameters to custom node via wire_to_custom
• Set HLSL code via set_custom_code
• Connect to output via connect_output
• Capture preview via material_preview
• Test live_coding compile and status operations
• Test editor_exit shows save dialog for dirty packages

🤖 Generated with Claude Code