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/index.js

@@ -195,7 +195,6 @@ const app = new Elysia()
           id: payload.userId,
           email: payload.email,
           callsign: payload.callsign,
-          role: payload.role,
           isAdmin: payload.isAdmin,
           impersonatedBy: payload.impersonatedBy, // Admin ID if impersonating
         },
@@ -400,7 +399,6 @@ const app = new Elysia()
         userId: user.id,
         email: user.email,
         callsign: user.callsign,
-        role: user.role,
         isAdmin: user.isAdmin,
         exp,
       });
@@ -1139,7 +1137,7 @@ const app = new Elysia()
 
   /**
    * POST /api/admin/users/:userId/role
-   * Update user role (admin only)
+   * Update user admin status (admin only)
    */
   .post('/api/admin/users/:userId/role', async ({ user, params, body, set }) => {
     if (!user || !user.isAdmin) {
@@ -1153,26 +1151,21 @@ const app = new Elysia()
       return { success: false, error: 'Invalid user ID' };
     }
 
-    const { role, isAdmin } = body;
+    const { isAdmin } = body;
 
-    if (!role || typeof isAdmin !== 'boolean') {
+    if (typeof isAdmin !== 'boolean') {
       set.status = 400;
-      return { success: false, error: 'role and isAdmin are required' };
-    }
-
-    if (!['user', 'admin'].includes(role)) {
-      set.status = 400;
-      return { success: false, error: 'Invalid role' };
+      return { success: false, error: 'isAdmin (boolean) is required' };
     }
 
     try {
-      await changeUserRole(user.id, targetUserId, role, isAdmin);
+      await changeUserRole(user.id, targetUserId, isAdmin);
       return {
         success: true,
-        message: 'User role updated successfully',
+        message: 'User admin status updated successfully',
       };
     } catch (error) {
-      logger.error('Error updating user role', { error: error.message, userId: user.id });
+      logger.error('Error updating user admin status', { error: error.message, userId: user.id });
       set.status = 400;
       return {
         success: false,
@@ -1238,7 +1231,6 @@ const app = new Elysia()
         userId: targetUser.id,
         email: targetUser.email,
         callsign: targetUser.callsign,
-        role: targetUser.role,
         isAdmin: targetUser.isAdmin,
         impersonatedBy: user.id, // Admin ID who started impersonation
         exp,
@@ -1299,7 +1291,6 @@ const app = new Elysia()
         userId: adminUser.id,
         email: adminUser.email,
         callsign: adminUser.callsign,
-        role: adminUser.role,
         isAdmin: adminUser.isAdmin,
         exp,
       });