Resolves#2997
## Description:
### New stuff
- Nations can upgrade structures now. They do it if they have too many
structures compared to their territory size
- They prefer to upgrade stuff thats protected by SAMs (based on
difficulty)
- Updated the build order, it also depends a bit on the difficulty now
(easy nations build less SAMs)
- Nations can handle extreme amounts of gold now. 500M starting gold? no
problem. Previously they only built cities
- They stop saving up for MIRV if they can afford it (in some old Enzo
"impossible difficulty experiment" videos you could see nations with
like 300M gold...)
- The save-up-target changes when bombs / hydros / MIRVs are disabled
- Added many checks for disabled units. For example: Don't build SAMs
when missile silos are disabled, focus on factories when ports are
disabled
- Updated the `structureSpawnTileValue` method, SAM-placement depends a
bit on the difficulty now
### Refactor
- Moved all structure related nation code into
`NationStructureBehavior.ts`
- Split up the good old `structureSpawnTileValue` method to make it more
readable
- Cleaned up NationExecution a bit
### A screenshot
<img width="1681" height="755" alt="Screenshot 2026-02-08 001108"
src="https://github.com/user-attachments/assets/c9b3df01-41ca-4c68-b450-b20e7d7d910a"
/>
## Please complete the following:
- [X] I have added screenshots for all UI updates
- [X] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [X] I have added relevant tests to the test directory
- [X] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
## Please put your Discord username so you can be contacted if a bug or
regression is found:
FloPinguin
VariableVince