feat: show Role and Usage/Quota columns on the Accounts list

Created At is replaced with two columns that previously required
opening each account individually: Role (badge, resolved against
x:UserRoles specifically since the list's merged User/Group field
definitions otherwise resolve `roles` against the wrong object) and
Usage / Quota (usedDiskQuota vs quotas.maxDiskQuota, "Unlimited" when
no limit is set).

Also makes renderCellValue's generic 'object' case resolve variant
labels via schema.schemas, instead of only ever printing the raw
@type string.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/i18n/en.json

@@ -313,7 +313,8 @@
     "showing": "Showing {{from}}-{{to}} of {{total}} {{name}}",
     "showingItems": "Showing {{count}} items",
     "sort": "Sort",
-    "unknownError": "Unknown error"
+    "unknownError": "Unknown error",
+    "unlimitedQuota": "Unlimited"
   },
   "login": {
     "continue": "Continue",