Nitro V3 update: CLI-only (Linux), settings via .env

- Moved Nitro V3 update from web UI (Commandocentrum) to CLI-only
- Removed configure paths form and runUpdateNitrov3() from admin panel
- update-Nitrov3.sh now loads .env automatically from its directory
- Added all NITRO_* env vars to .env.example.linux and .env
- Removed configurable paths from database (replaced by .env)
- Updated README and CHANGELOG

lang/en.json

@@ -52,6 +52,7 @@
   "commandocentrum.emulator_backups_desc": "View and restore emulator backups",
   "commandocentrum.restore": "Restore",
   "commandocentrum.nitro_client": "Nitro Client",
+  "commandocentrum.nitro_cli_only": "This script can only be run via command line. Use: bash update-Nitrov3.sh\n\nSettings are configured in the .env file in the project root.",
   "commandocentrum.clothing_sync": "Clothing Sync",
   "commandocentrum.clothing_sync_desc": "Sync catalog clothing from FigureMap",
   "commandocentrum.sync": "Sync",