Incorrect `maxzoom` Metadata in PMTiles

[FabianRechsteiner]

Bug Report: Incorrect maxzoom Metadata in PMTiles

Description:
I created a PMTiles file using the BBOX server with maxzoom=15 during export. However, the metadata of the resulting file incorrectly sets maxzoom to 24, causing Maputnik to only display data up to zoom level 15 and prevent higher zoom levels from showing. This seems to be a bug in the BBOX server, as the maxzoom should be correctly set to match the available zoom levels.

Using the PMTiles Viewer, I was able to confirm that the metadata incorrectly specifies maxzoom=24.

The command I used to create the PMTiles file was:

docker exec -it bbox bbox-server seed \
  --pm-path=/tmp/av_tg.pmtiles \
  --tileset=av \
  --maxzoom=15 \
  --extent=958098.9550,5990503.7037,1072266.1174,6066003.8084

The file is now hosted here: https://raw.githubusercontent.com/FabianRechsteiner/vector-tiles-benchmark/master/data/av_tg.pmtiles.

Steps to Reproduce:

1. Create a PMTiles file using the BBOX server with maxzoom=15.
2. Check the metadata of the resulting PMTiles file in the PMTiles Viewer.
3. Notice that maxzoom is incorrectly set to 24.

Expected Behavior:
The maxzoom should match the maximum available zoom level, which in this case should be 15.