feat: name systems in the install manifests

Each manifest carries system_titles, the name the site prints for every system its files list (Sony PlayStation, not sony-playstation or psx), so the installer can show it. Older installers ignore the field.

install/nextui.json

@@ -6,7 +6,7 @@
   "platform": "nextui",
   "display_name": "NextUI",
   "version": "1.0",
-  "generated": "2026-10-23T07:11:31Z",
+  "generated": "2026-10-23T12:47:02Z",
   "base_destination": "",
   "detect": [
     {
@@ -88,6 +88,7 @@
   },
   "system_cores": {},
   "system_names": {},
+  "system_titles": {},
   "files": [
     {
       "dest": "Bios/FBN/fbneo/hiscore.dat",