feat(accounts): add Usage/Quota column to Groups, show unlimited as ∞

Groups have real usedDiskQuota/quotas fields, same as Users, but the
Groups list schema doesn't expose usage as a column any more than the
Accounts list did — extend the existing account-quota-usage-column
deviation to x:Account/Group too (SCHEMA_DEVIATIONS.md updated).

The isAccountsList gate that resolved/rendered quotaUsage was hardcoded
to viewName === 'x:Account/User', so it silently no-oped for Groups.
Replaced with hasQuotaUsageColumn, derived from whether the resolved
list's own columns include the synthetic quotaUsage column — works for
any list withAccountListColumns patches, not just a hardcoded pair of
view names.

Also: "Unlimited" (no quota configured) now renders as "∞" instead of
the word, matching the size formatting style used elsewhere in the
column.

src/i18n/en.json

@@ -319,7 +319,7 @@
     "showingItems": "Showing {{count}} items",
     "sort": "Sort",
     "unknownError": "Unknown error",
-    "unlimitedQuota": "Unlimited",
+    "unlimitedQuota": "∞",
     "negativeQuotaInfoAria": "Why is disk usage negative?",
     "negativeQuotaTooltip": "This disk-usage counter is out of sync (often after a migration or reset). Schedule a task: Perform account maintenance operations → Recalculate storage quota usage for the account. Or for all accounts: Perform store maintenance operations → Reset all user quotas."
   },