Add keyboard nudging and limit movable objects

[sundsoffice-tech]

Summary

• add arrow-key nudging for selected cabin, counter, screen, and truss selections with per-mount axis clamping
• cap detailed counter and screen counts (including legacy conversions) to prevent scene overload
• keep ground-plane items locked to the stand footprint when nudged via keyboard

Testing

• npm run build

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Codex Task

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Legacy screen heights double-add floor offset

The new normalisation only subtracts floorHeight when heightFromFloor exceeds wallHeight + floorHeight, which misses legacy data where heightFromFloor already included the floor offset (previous converter stored floorHeight + 1.6). For raised floors, those stored values (e.g. 1.8 when floorHeight is 0.2) fall below the threshold, so heightFromFloor stays absolute and the worldY = floorHeight + heightFromFloor calculation just below adds the floor offset a second time. Any saved configuration from the previous version with a raised floor will render and drag screens too high by exactly the floor height, breaking layout and nudging accuracy until the user manually repositions them.

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