requirements for demolishing buildings in construction queue

docs/requirements.md

@@ -60,7 +60,7 @@ Output port indicators are not building tiles themselves. A building may have mo
 - REQ-BLD-PLACE: Clicking a valid tile in builder mode places a construction site and adds it to the build queue, consuming building blocks from the global stock.
 - REQ-BLD-PLACE-VALID: A placement position is valid only if (a) every footprint cell in the rotated `surface_mask` is satisfied by the underlying terrain — `A` cells coincide with asteroid tiles, `S` cells coincide with space tiles — and (b) no footprint cell overlaps an existing placed building or construction site. Affordability is not re-checked at placement time: builder mode cannot be entered when the player cannot afford the building (REQ-UI-BUILD-DISABLED), so once in builder mode the only placement validity concerns are terrain and overlap. The ghost (REQ-BLD-GHOST) is rendered in a distinct "invalid" color when the current cursor position fails either condition.
 - REQ-BLD-BELT-DRAG: For belts, the player can click and drag across multiple tiles to place a construction site on each tile in one gesture.
-- REQ-BLD-DEMOLISH: The player can demolish a placed factory building. Demolition returns `world.toml [world].refund_percentage` percent of the original building block cost (default 75%) to the global stock. The HQ and player defence stations cannot be demolished.
+- REQ-BLD-DEMOLISH: The player can demolish a placed factory building. Demolition returns `world.toml [world].refund_percentage` percent of the original building block cost (default 75%) to the global stock. Exception: if the building is still in the construction queue (not yet fully built, including the one currently being constructed), it is removed from the queue and the **full** building block cost is refunded. The HQ and player defence stations cannot be demolished.
 
 ## Building Types