2.0.0 serves its MapLibre worker as a .mjs file, which nginx's stock
mime.types doesn't map, breaking the map on both fresh installs and
updates. Also drops the now-dead JWT key generation/env vars (2.0.0
uses opaque session tokens), clears stale frontend build output on
update via CLEAN_INSTALL+KEEP instead of accumulating it forever,
backs up the database before updating, bumps new installs straight
to PostgreSQL 18/PostGIS 3.6, and raises the default disk size after
hitting real space pressure during a live upgrade.
Tobias