Polish settings, add matching defaults, drop pkg2zip, externalize infra config

- Rework Settings tab into grouped sections
- Add preferred-region matching and full-hash-by-default setting
- Replace combo-box square arrow with a proper chevron
- Fix UMD Refresh button (clicked bool was clearing the view)
- Remove pkg2zip.exe fallback (pure-Python decryptor is the primary path)
- Move LAN IP/share paths to .env; use example defaults in config

.gitignore

@@ -16,4 +16,7 @@ data/*.pbp
 data/ps1_templates/
 
 # nps tsv files
-data/nps/*.tsv
+data/nps/*.tsv
+
+# Local environment overrides (LAN paths, secrets). See .env.example
+.env