refactor: remove redundant role field, keep only is_admin

- Remove role column from users schema (migration 0003)
- Update auth and admin services to use is_admin only
- Remove role from JWT token payloads
- Update admin CLI to use is_admin field
- Update frontend admin page to use isAdmin boolean
- Fix security: remove console.log dumping credentials in settings

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

src/backend/services/admin.service.js

@@ -122,7 +122,6 @@ export async function getUserStats() {
       id: users.id,
       email: users.email,
       callsign: users.callsign,
-      role: users.role,
       isAdmin: users.isAdmin,
       qsoCount: sql`CAST(COUNT(${qsos.id}) AS INTEGER)`,
       lotwConfirmed: sql`CAST(SUM(CASE WHEN ${qsos.lotwQslRstatus} = 'Y' THEN 1 ELSE 0 END) AS INTEGER)`,
@@ -250,19 +249,18 @@ export async function getImpersonationStatus(adminId, { limit = 10 } = {}) {
 }
 
 /**
- * Update user role (admin operation)
+ * Update user admin status (admin operation)
  * @param {number} adminId - Admin user ID making the change
  * @param {number} targetUserId - User ID to update
- * @param {string} newRole - New role ('user' or 'admin')
  * @param {boolean} newIsAdmin - New admin flag
  * @returns {Promise<void>}
  * @throws {Error} If not admin or would remove last admin
  */
-export async function changeUserRole(adminId, targetUserId, newRole, newIsAdmin) {
+export async function changeUserRole(adminId, targetUserId, newIsAdmin) {
   // Verify the requester is an admin
   const requesterIsAdmin = await isAdmin(adminId);
   if (!requesterIsAdmin) {
-    throw new Error('Only admins can change user roles');
+    throw new Error('Only admins can change user admin status');
   }
 
   // Get target user
@@ -283,11 +281,10 @@ export async function changeUserRole(adminId, targetUserId, newRole, newIsAdmin)
     }
   }
 
-  // Update role
+  // Update admin status
   await db
     .update(users)
     .set({
-      role: newRole,
       isAdmin: newIsAdmin ? 1 : 0,
       updatedAt: new Date(),
     })
@@ -295,8 +292,6 @@ export async function changeUserRole(adminId, targetUserId, newRole, newIsAdmin)
 
   // Log action
   await logAdminAction(adminId, 'role_change', targetUserId, {
-    oldRole: targetUser.role,
-    newRole: newRole,
     oldIsAdmin: targetUser.isAdmin,
     newIsAdmin: newIsAdmin,
   });