Flickering buid preview

### Description

Switching from a smaller to a larger building while the game is paused without moving mouse or changing the buildings facing causes flickering of the build preview square.

Changing the build queue while the game is paused without moving mouse shows outdated overlap information.

### Reproduction

Changing previewed building:

1. Pause the game.
2. Select a constructor
3. Keep the cursor fixed over one build position and keep the same facing.
4. Preview a 2x2 building such as wind turbine or scorpion where it overlaps an existing building or queue entry.
5. Without moving the cursor or changing the facing, switch to a larger building such as adv botlab or experimental gantry.
6. The build preview starts to flicker

https://github.com/user-attachments/assets/6b05e70f-e38b-4390-b254-86fc4ce54956

Changing build queue

1. Pause the game.
2. Select a constructor
3. Queue a Build
4. Preview another build overlapping over the existing so it's shown partly red
5. Change the build queue, e.g. by pressing "N", without moving the cursor or changing the facing
6. The build preview shows the status from before the change

https://github.com/user-attachments/assets/5bab2ba9-6ac9-46f3-9861-60dc88cfc6b8

Start by reproducing both paused-game cases: switch from a smaller to a larger building, then change the build queue while the cursor and facing stay fixed. Trace the build-preview update path reached by those actions. Done means the preview no longer flickers and its overlap status reflects the current building or queue without requiring mouse movement.

Written by the indexing model from the issue text.