fix(mcp): distinguish roof support levels from stories

packages/mcp/src/resources/agent-guide.ts

@@ -27,6 +27,7 @@ export const AGENT_GUIDE = [
   '- Use `create_story_shell` once per floor/story to avoid cross-level wall ownership mistakes.',
   '- Use `create_stair_between_levels` for stairs. It creates a straight stair and one rectangular manual slab/ceiling opening while disabling automatic stair-opening mode, avoiding duplicate or irregular holes.',
   '- Roofs are containers with roof segments and should be isolated on a dedicated roof level for solo/exploded level views. Use `create_roof`; by default it creates a roof level above the reference occupied level. Do not attach roofs directly to the top occupied floor unless explicitly requested.',
+  '- Story count means occupied stories, not raw level count. A two-story house may correctly have three levels when the third level has metadata role `roof`; do not delete roof/support levels to satisfy a requested story count.',
   '- Use `pascal://constraints/{levelId}` when you need existing slab holes or wall footprints for precise placement.',
   '',
   '## Scene model facts exposed here so agents do not need repo inspection',
@@ -35,6 +36,7 @@ export const AGENT_GUIDE = [
   '- A story wall height is normally 2.4-3.0m; wall thickness is normally 0.1-0.3m.',
   '- Slab and ceiling holes are polygon arrays. Manual stair openings should have `holeMetadata` with source `manual` and a single rectangular polygon.',
   '- Dedicated roof levels use metadata role `roof` and normally contain the roof only; the top occupied level keeps its own walls, rooms, slabs, and ceiling.',
+  '- `verify_scene` reports `occupiedStoryCount`, `supportLevelCount`, and `roofLevelIds`; use those fields instead of `levelCount` when checking story-count requirements.',
   '- Saved site children can contain embedded building objects for compatibility, but tools handle parent/child bookkeeping. Prefer tools over raw graph surgery for common construction.',
   '- `validate_scene` checks schema correctness. `verify_scene` checks practical layout issues such as empty levels, missing rooms/floors/doors, bad openings, stair obstructions, and suspicious multi-story wall heights.',
   '',