feat(auth): make upload review a separate grant instead of an admin privilege

Reviewing the upload queue is now a per-user flag (reviews_uploads), not part
of the admin role: several people can hold it, a moderator can have it, and an
admin may not. Only admins grant or revoke it; existing admins keep it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/i18n/locales/en/admin.json

@@ -1,7 +1,7 @@
 {
   "users": {
     "title": "Users",
-    "subtitle": "Create users and moderators, manage roles, reset passwords, block accounts",
+    "subtitle": "Create users and moderators, manage roles, upload review, reset passwords, block accounts",
     "create": "Create user",
     "search": "Name or username",
     "all": "All",
@@ -20,6 +20,9 @@
     "block": "Block",
     "unblock": "Unblock",
     "make_role": "Make {{role}}",
+    "review_uploads": "Upload review",
+    "grant_review": "Grant upload review",
+    "revoke_review": "Revoke upload review",
     "delete": "Delete",
     "delete_confirm": "Delete {{username}}? Their history and likes will be lost.",
     "block_confirm": "Block {{username}}? All their sessions will end.",
@@ -36,6 +39,8 @@
     "username_hint": "Latin letters, digits, \".\", \"_\", \"-\"",
     "display_name": "Name",
     "role": "Role",
+    "review_uploads": "Upload review",
+    "review_uploads_hint": "They can review the upload queue. This is not a role: several people can have it, and an admin might not.",
     "password_note": "The server will generate a password and show it once.",
     "submit": "Create"
   },