refactor: remove rails4-autocomplete and jquery-ui-rails

Removes rails4-autocomplete (12+ years unmaintained) and jquery-ui-rails
dependencies that have been non-functional since April 2022.

The autocomplete feature for the skill_list field was accidentally broken
during Bootstrap 5 migration (PR #1745) and has remained broken for nearly
3 years without user complaints.

Analysis confirmed:
- Feature broken since April 2022 (Bootstrap 5 migration)
- Zero usage of jQuery UI widgets across entire codebase
- Both gems added together in 2015 exclusively for autocomplete
- No test coverage for autocomplete functionality
- skill_list field continues working with manual comma-separated entry

Removes:
- rails4-autocomplete gem (last updated April 2014)
- jquery-ui-rails gem (single-purpose dependency)
- Controller autocomplete declaration
- Autocomplete route endpoint
- JavaScript and CSS requires

Bundle size savings: ~120KB

Closes #2445

Documentation: docs/rails4-autocomplete-investigation.md

Author: mroderick

Gemfile

@@ -23,7 +23,6 @@ gem 'friendly_id'
 gem 'haml'
 gem 'high_voltage'
 gem 'jquery-rails'
-gem 'jquery-ui-rails'
 
 # Use Active Storage variant
 gem 'image_processing'
@@ -37,7 +36,6 @@ gem 'pickadate-rails'
 gem 'premailer-rails'
 
 gem 'pundit'
-gem 'rails4-autocomplete'
 gem 'reline' # LOCKED: Added because of readline is not part of Ruby 3.5.0
 gem 'rolify'
 # Use Sass to process CSS

Gemfile.lock

@@ -285,8 +285,6 @@ GEM
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    jquery-ui-rails (6.0.1)
-      railties (>= 3.2.16)
     json (2.18.0)
     jwt (2.7.1)
     language_server-protocol (3.17.0.5)
@@ -460,8 +458,6 @@ GEM
     rails-html-sanitizer (1.6.2)
       loofah (~> 2.21)
       nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
-    rails4-autocomplete (1.1.1)
-      rails (>= 3.0)
     rails_semantic_logger (4.19.0)
       rack
       railties (>= 5.1)
@@ -682,7 +678,6 @@ DEPENDENCIES
   importmap-rails
   irb
   jquery-rails
-  jquery-ui-rails
   launchy
   letter_opener
   listen (~> 3.10)
@@ -705,7 +700,6 @@ DEPENDENCIES
   rack-mini-profiler (~> 4.0)
   rails (~> 8.1.2)
   rails-html-sanitizer (~> 1.6.2)
-  rails4-autocomplete
   rails_semantic_logger
   reline
   rolify

app/assets/javascripts/application.js

@@ -15,8 +15,6 @@
 //= require jquery
 //= require rails-ujs
 //= require activestorage
-//= require jquery-ui
-//= require autocomplete-rails
 //= require chosen-jquery
 //= require 'jsimple-star-rating.min.js'
 //= require pickadate/picker

app/assets/stylesheets/application.scss

@@ -15,7 +15,6 @@
  *= require pickadate/classic.date
  *= require pickadate/classic.time
  *= require chosen
- *= require jquery-ui
  */
 
 @import "partials/colors";

app/controllers/members_controller.rb

@@ -5,8 +5,6 @@ class MembersController < ApplicationController
   before_action :authenticate_member!, only: %i[edit step2 profile]
   before_action :suppress_notices, only: %i[step2]
 
-  autocomplete :skill, :name, class_name: 'ActsAsTaggableOn::Tag'
-
   def new
     @page_title = 'Sign up'
   end

config/routes.rb

@@ -25,10 +25,6 @@
     resource :details, only: %i[edit update]
   end
 
-  resource :members do
-    get :autocomplete_skill_name, on: :collection
-  end
-
   get '/profile' => 'members#profile', as: :profile
 
   resources :subscriptions, only: %i[index create]