Port PSN pkg decryption to pure Python (drop Wine requirement)

app/transfers.py

@@ -469,8 +469,8 @@ class NoPayStationSource(Source):
     """Browse NoPayStation .pkg lists and install PSP/PSX PSN content.
 
     ``content_type`` is ``"psp"`` (PSP_GAMES.tsv) or ``"psx"`` (PSX_GAMES.tsv).
-    Downloading decrypts the ``.pkg`` with the ``pkg2zip`` binary and writes a
-    ``<TITLE_ID>/EBOOT.PBP`` game folder into ``dest_dir``.
+    Downloading decrypts the ``.pkg`` with the bundled pure-Python decryptor
+    and writes a ``<TITLE_ID>/EBOOT.PBP`` game folder into ``dest_dir``.
     """
 
     label = "NoPayStation"
@@ -490,12 +490,9 @@ class NoPayStationSource(Source):
         dest_dir = Path(dest_dir)
         dest_dir.mkdir(parents=True, exist_ok=True)
 
+        # The bundled Python decryptor handles PSP/PSX directly; pkg2zip is
+        # only an optional fallback if a binary happens to be configured.
         pkg2zip = nopaystation.find_pkg2zip(self.pkg2zip)
-        if pkg2zip is None:
-            raise RuntimeError(
-                "pkg2zip not found — install it (https://github.com/mmozeiko/pkg2zip) "
-                "or set its path in Settings → Store."
-            )
         title_id = item.get("title_id") or item.get("content_id") or ""
         pkg_name = re.sub(r"[^A-Za-z0-9_-]", "", title_id) or "pkg"
         tmp = Path(tempfile.mkdtemp(prefix="nps-download-"))