Future: Add schematic-to-CraftDAG / tutorial adapter

[madawei2699]

Context

Inspired by Arnis: the most valuable Minecraft generators are often stable data pipelines, not autonomous agents.

For CraftDAG, the most relevant future input adapter is not OSM/world generation, but existing Minecraft structure files.

Idea

Add a future adapter that can read an existing .schem / .litematic file and derive useful build-planning outputs:

.schem / .litematic
→ VoxelPlan
→ material list
→ layer guide
→ optional component inference
→ simplified tutorial

Why this matters

This would let MinePilot support workflows such as:

• upload an existing schematic
• inspect it in 3D
• get material list
• get layer-by-layer guide
• simplify or restyle later

This may be more practical than trying to generate large buildings from scratch.

Suggested phases

1. Parse .schem into VoxelPlan.
2. Generate material list and layer guide from imported VoxelPlan.
3. Add basic component inference later, such as foundation / walls / roof / decoration.
4. Expose this through MinePilot as schematic-to-tutorial.

Non-goals

• Do not implement this before MinePilot playground MVP.
• Do not attempt perfect semantic reconstruction in the first version.
• Do not add OSM/geographic generation here.

Acceptance criteria for first implementation

• A .schem file can be parsed into VoxelPlan.
• Imported VoxelPlan round-trips through material/layer generation.
• Tests cover at least one fixture schematic.

[madawei2699]

Roadmap note after the schematic-preview MVP:

This issue is still useful, but it should probably follow the new component/LLM authoring track:

• Design architectural component primitives for LLM-authored builds #31 Design architectural component primitives for LLM-authored builds
• Implement component-plan expansion into CraftDAG #32 Implement component-plan expansion into CraftDAG
• Create LLM authoring contract for CraftDAG plans #33 Create LLM authoring contract for CraftDAG plans

The reason is that import/adapters are valuable, but the next core unlock is a safe intermediate component IR: more expressive than raw coordinate nodes, but still deterministic and expandable into validated CraftDAG. Once that layer exists, adapters can target either VoxelPlan or the component/CraftDAG layer depending on how much semantic structure they can recover.