Map autosave regression after maps moved to server-global SavedDataStorage

Expected behavior

Filled map data should be periodically saved to disk according to ticks-per.autosave, like on Paper.

Observed/Actual behavior

Map data is not saved during normal runtime and is only written during a clean shutdown.

This appears to be a regression of #372.

Current map creation/access uses the server-global storage:

server.getDataStorage()

but Folia's map autosave still calls:

world.getDataStorage().saveMaps();

These are different SavedDataStorage instances, so the periodic autosave scans the wrong storage.

Steps/models to reproduce

1. Start Folia with:

ticks-per:
  autosave: 6000

2. Create a new filled map or update an existing one.
3. Wait longer than 5 minutes.
4. Check world/data/minecraft/maps/.

The map .dat file is not created or updated during runtime.

5. Stop the server normally.

The map data is then written during shutdown.

Plugin and Datapack List

None.

Folia version

[13:52:55 INFO]: Checking version, please wait...
[13:52:55 INFO]: This server is running Folia version 26.2-7-ver/26.2.x@14b7fee (2026-08-25T13:29:28Z) (Implementing API version 26.2.build.7-beta)
You are running the latest version

Other

Map autosaving was originally added in 44f4aabe to fix #372.

After map SavedData was moved to MinecraftServer#getDataStorage(), Folia's autosave path continued using world.getDataStorage().

The likely fix is to make map autosaving server-global and call:

MinecraftServer.getServer().getDataStorage().saveMaps();

once per autosave interval instead of once per world.

Start by tracing the autosave path that calls world.getDataStorage().saveMaps() and compare it with map creation through server.getDataStorage(). Reproduce with ticks-per.autosave set to 6000 and inspect world/data/minecraft/maps/. Done means filled map data is written or updated during runtime once per autosave interval, rather than only at shutdown.