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

app/pipeline.py

@@ -2,9 +2,9 @@
 from . import iso_reader, matcher, namer
 
 
-def identify(conn, record):
+def identify(conn, record, prefer_region=None):
     """Return ``{method, release, serial, canonical}`` for a scanned disc record."""
-    method, release = matcher.match(conn, record)
+    method, release = matcher.match(conn, record, prefer_region=prefer_region)
     return identify_with_release(record, release, method)