feat(hackathon): add searchable city select component

- Created CitySelect component with real-time filtering
- Supports 516 Indonesian cities with array filtering
- Added search functionality for better UX
- Integrated with react-hook-form in user onboarding
- Includes clear button and auto-close on outside click

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/hackathon/src/app/onboarding/user/page.tsx

@@ -13,7 +13,7 @@ import {
 } from '@imphnen-frontend-service/service';
 import { zodResolver } from '@hookform/resolvers/zod';
 
-import INDONESIAN_CITIES from '../../../constants/cities';
+import { CitySelect } from '../../../components/city-select';
 
 const ROLE_OPTIONS = [
   'Frontend Developer',
@@ -172,24 +172,12 @@ const UserOnboardingPage: FC = (): ReactElement => {
               control={form.control}
               name="location"
               render={({ field, fieldState }) => (
-                <div>
-                  <select
-                    {...field}
-                    className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent"
-                  >
-                    <option value="">Select your city</option>
-                    {INDONESIAN_CITIES.map((city) => (
-                      <option key={city} value={city}>
-                        {city}
-                      </option>
-                    ))}
-                  </select>
-                  {fieldState.error && (
-                    <p className="text-sm text-red-500 mt-1">
-                      {fieldState.error.message}
-                    </p>
-                  )}
-                </div>
+                <CitySelect
+                  value={field.value}
+                  onChange={field.onChange}
+                  error={fieldState.error?.message}
+                  placeholder="Search your city..."
+                />
               )}
             />
           </div>

apps/hackathon/src/components/city-select.tsx

@@ -0,0 +1,115 @@
+import { FC, useState, useRef, useEffect } from 'react';
+import INDONESIAN_CITIES from '../constants/cities';
+
+interface CitySelectProps {
+  value: string;
+  onChange: (value: string) => void;
+  error?: string;
+  placeholder?: string;
+}
+
+export const CitySelect: FC<CitySelectProps> = ({
+  value,
+  onChange,
+  error,
+  placeholder = 'Search your city...',
+}) => {
+  const [isOpen, setIsOpen] = useState(false);
+  const [searchQuery, setSearchQuery] = useState('');
+  const dropdownRef = useRef<HTMLDivElement>(null);
+  const inputRef = useRef<HTMLInputElement>(null);
+
+  // Filter cities based on search query
+  const filteredCities = INDONESIAN_CITIES.filter((city) =>
+    city.toLowerCase().includes(searchQuery.toLowerCase())
+  );
+
+  // Close dropdown when clicking outside
+  useEffect(() => {
+    const handleClickOutside = (event: MouseEvent) => {
+      if (
+        dropdownRef.current &&
+        !dropdownRef.current.contains(event.target as Node)
+      ) {
+        setIsOpen(false);
+      }
+    };
+
+    document.addEventListener('mousedown', handleClickOutside);
+    return () => document.removeEventListener('mousedown', handleClickOutside);
+  }, []);
+
+  const handleSelectCity = (city: string) => {
+    onChange(city);
+    setSearchQuery('');
+    setIsOpen(false);
+  };
+
+  const handleInputClick = () => {
+    setIsOpen(true);
+    setSearchQuery('');
+  };
+
+  const handleClearSelection = () => {
+    onChange('');
+    setSearchQuery('');
+    setIsOpen(true);
+    inputRef.current?.focus();
+  };
+
+  return (
+    <div className="relative" ref={dropdownRef}>
+      <div className="relative">
+        <input
+          ref={inputRef}
+          type="text"
+          value={isOpen ? searchQuery : value}
+          onChange={(e) => {
+            setSearchQuery(e.target.value);
+            setIsOpen(true);
+          }}
+          onClick={handleInputClick}
+          placeholder={placeholder}
+          className={`w-full px-3 py-2 border rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent ${
+            error ? 'border-red-500' : 'border-gray-300'
+          }`}
+        />
+        {value && !isOpen && (
+          <button
+            type="button"
+            onClick={handleClearSelection}
+            className="absolute right-3 top-1/2 -translate-y-1/2 text-gray-400 hover:text-gray-600"
+          >
+            ✕
+          </button>
+        )}
+      </div>
+
+      {error && <p className="text-sm text-red-500 mt-1">{error}</p>}
+
+      {isOpen && (
+        <div className="absolute z-50 w-full mt-1 bg-white border border-gray-300 rounded-lg shadow-lg max-h-60 overflow-y-auto">
+          {filteredCities.length > 0 ? (
+            <ul className="py-1">
+              {filteredCities.map((city) => (
+                <li
+                  key={city}
+                  onClick={() => handleSelectCity(city)}
+                  className={`px-3 py-2 cursor-pointer hover:bg-blue-50 ${
+                    value === city ? 'bg-blue-100 text-blue-700' : ''
+                  }`}
+                >
+                  {city}
+                </li>
+              ))}
+            </ul>
+          ) : (
+            <div className="px-3 py-2 text-gray-500 text-sm">
+              No cities found
+            </div>
+          )}
+        </div>
+      )}
+    </div>
+  );
+};