feat(auth): implement role-based access control (RBAC)

Add roles, permissions, and user_roles tables with default seed data
Protect backend API endpoints with granular permission checks
Add admin UI for managing users, roles, and permissions
Update frontend views to conditionally render actions based on permissions

frontend/src/components/EntityDiscussionPanel.vue

@@ -36,7 +36,11 @@ const commentMaxLength = 1000;
 let requestId = 0;
 let removeAuthListener: (() => void) | null = null;
 
-const canComment = computed(() => currentUser.value?.emailVerified === true);
+function can(permissionKey: string) {
+  return currentUser.value?.permissions.includes(permissionKey) === true;
+}
+
+const canComment = computed(() => can('discussions.comments.create'));
 const charactersLeft = computed(() => Math.max(0, commentMaxLength - body.value.length));
 const commentTotal = computed(() => comments.value.reduce((total, comment) => total + 1 + comment.replies.length, 0));
 
@@ -108,7 +112,11 @@ function clearCommentError(key: string) {
 }
 
 function canManageComment(comment: EntityDiscussionComment) {
-  return !comment.deleted && currentUser.value?.id === comment.author?.id;
+  return (
+    !comment.deleted &&
+    ((currentUser.value?.id === comment.author?.id && can('discussions.comments.delete')) ||
+      can('discussions.comments.delete-any'))
+  );
 }
 
 function commentAuthorName(comment: EntityDiscussionComment) {