Feat/stair ceiling slab cutout

[sudhir9297]

Stairs, Slabs & Ceiling Cutouts

• Added stair opening data:
  • fromLevelId
  • toLevelId
  • slabOpeningMode
  • openingOffset
• Added holeMetadata support for both slabs and ceilings.
• Built automatic synchronization between stairs and slab/ceiling cutouts.
• Wired cutout sync into the stair system for initial load and live updates.
• Added stair panel controls for:
  • From/To level selection
  • Opening configuration
• Updated stair tool defaults for improved initial behavior.
• Fixed stair placement so adding stairs on a specific floor keeps them on that floor.

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Hole Behavior & UI

• Updated slab, ceiling, and manual hole UI to correctly preserve:
  • Manually created holes
  • Stair-generated holes
• Ensured both types coexist without conflicts.

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Stair Cutout Geometry

• Implemented straight stair cutouts.
• Implemented landing cutouts and merged them with connected flight cutouts.
• Added support for larger straight-flight cutouts.
• Limited flight cutouts to only affect the top side of the flight.
• Added ceiling cutouts alongside slab cutouts for full vertical consistency.
• Added spiral stair circular cutout support.