feat(library): show playtime per platform on game detail

Hero and library card show the set total. Fall back to the
row's own minutes when the API sends no total.

public/i18n/de.json

@@ -796,6 +796,12 @@
     "OTHER_OWNERS_other": "{{count}} andere Besitzer",
     "SHOW_OWNERS": "Zeigen, wer es besitzt"
   },
+  "PLATFORMS": {
+    "TITLE": "Spielzeit pro Plattform",
+    "TOTAL": "Gesamt",
+    "LAST_PLAYED": "Zuletzt gespielt",
+    "NEVER": "nie"
+  },
   "LINKS": {
     "ALSO_IN_LIBRARY": "Auch in deiner Bibliothek:",
     "SAME_AS": "Dasselbe Spiel wie...",