refactor: Delete isPlainObject type guard and replace its usages with direct typeof checks.

frontend/src/settings/components/CapabilityDropdown.tsx

@@ -7,7 +7,7 @@ import {
 } from 'react';
 import type { JSX } from 'react';
 import { CheckIcon, ChevronDownIcon } from '../../ui/icons';
-import { isPlainObject } from '../../utils/typeGuards';
+
 
 type CapabilityValue = string | number;
 
@@ -29,9 +29,7 @@ interface CapabilityDropdownProps {
   summaryLabel?: string;
 }
 
-const isCapabilityOption = (
-  option: CapabilityDropdownOption | CapabilityValue | null,
-): option is CapabilityDropdownOption => isPlainObject(option);
+
 
 const resolveCapabilityValue = (
   option: CapabilityDropdownOption | CapabilityValue | null,
@@ -39,8 +37,8 @@ const resolveCapabilityValue = (
   if (option == null) {
     return null;
   }
-  if (!isCapabilityOption(option)) {
-    return option as CapabilityValue;
+  if (typeof option !== 'object') {
+    return option;
   }
   if (option.value != null) {
     return option.value;
@@ -170,7 +168,7 @@ const CapabilityDropdown = ({
               }
               const label = formatLabel
                 ? formatLabel(value)
-                : (isCapabilityOption(option) && option?.label) || String(value);
+                : (typeof option === 'object' && option?.label) || String(value);
               const selected = selectedValues.includes(value);
               return (
                 <button

frontend/src/settings/sections/CapabilitySetsSection.tsx

@@ -8,7 +8,7 @@ import React, {
 import type { SettingsSectionConfig } from '../SettingsModal';
 import { IconX } from '../../ui/icons';
 import CapabilityDropdown, { CapabilityDropdownOption } from '../components/CapabilityDropdown';
-import { isPlainObject } from '../../utils/typeGuards';
+
 
 type CapabilityValue = string | number;
 type CapabilitySetId = string | number;
@@ -55,15 +55,14 @@ interface CapabilitySetsSectionProps {
 
 type CapabilityOptionInput = CapabilityDropdownOption | CapabilityValue | null;
 
-const isCapabilityOption = (option: CapabilityOptionInput): option is CapabilityDropdownOption =>
-  isPlainObject(option);
+
 
 const resolveCapabilityValue = (option: CapabilityOptionInput): CapabilityValue | null => {
   if (option == null) {
     return null;
   }
-  if (!isCapabilityOption(option)) {
-    return option as CapabilityValue;
+  if (typeof option === 'string' || typeof option === 'number') {
+    return option;
   }
   if (option.value != null) {
     return option.value as CapabilityValue;