Add Turbo Stream support for navigation item CRUD (#1004)

## Summary
- support Turbo Stream responses for navigation item creation and
deletion
- append/remove navigation items in real time using Turbo templates
- add DOM target for navigation items table

## Testing
- `bundle exec bundler-audit --update` *(fails: command not found)*
- `bundle exec rubocop` *(fails: command not found)*
- `bundle exec brakeman -q -w2` *(fails: command not found)*
- `bin/codex_style_guard` *(fails: command not found)*
- `bin/ci` *(fails: command not found)*

------
https://chatgpt.com/codex/tasks/task_e_689b64b451d08321a6cb73678bf9f765

Author: rsmithlal

app/controllers/better_together/navigation_items_controller.rb

@@ -32,15 +32,30 @@ def edit
       authorize @navigation_item
     end
 
-    def create
+    def create # rubocop:todo Metrics/AbcSize, Metrics/MethodLength
       @navigation_item = new_navigation_item
       @navigation_item.assign_attributes(navigation_item_params)
       authorize @navigation_item
-
-      if @navigation_item.save
-        redirect_to @navigation_area, only_path: true, notice: 'Navigation item was successfully created.'
-      else
-        render :new
+      respond_to do |format|
+        if @navigation_item.save
+          flash.now[:notice] = 'Navigation item was successfully created.'
+          format.html do
+            redirect_to @navigation_area, only_path: true,
+                                          notice: 'Navigation item was successfully created.'
+          end
+          format.turbo_stream { render :create }
+        else
+          format.html { render :new, status: :unprocessable_entity }
+          format.turbo_stream do
+            render turbo_stream: [
+              turbo_stream.update('form_errors', partial: 'layouts/better_together/errors',
+                                                 locals: { object: @navigation_item }),
+              turbo_stream.update('navigation_item_form', partial: 'better_together/navigation_items/form',
+                                                          locals: { navigation_item: @navigation_item,
+                                                                    navigation_area: @navigation_area })
+            ]
+          end
+        end
       end
     end
 
@@ -74,8 +89,15 @@ def update # rubocop:todo Metrics/AbcSize, Metrics/MethodLength
     def destroy
       authorize @navigation_item
       @navigation_item.destroy
-      redirect_to navigation_area_navigation_items_url(@navigation_area),
-                  notice: 'Navigation item was successfully destroyed.'
+      flash.now[:notice] = 'Navigation item was successfully destroyed.'
+
+      respond_to do |format|
+        format.html do
+          redirect_to navigation_area_navigation_items_url(@navigation_area),
+                      notice: 'Navigation item was successfully destroyed.'
+        end
+        format.turbo_stream { render :destroy }
+      end
     end
 
     private

app/views/better_together/navigation_items/_navigation_items_table.html.erb

@@ -12,7 +12,7 @@
       <th class="text-end"><%= t('globals.actions') %></th>
     </tr>
   </thead>
-  <tbody>
+  <tbody id="navigation_items">
     <%= render partial: 'better_together/navigation_items/navigation_item_row',
                collection: navigation_items,
                as: :item

app/views/better_together/navigation_items/create.turbo_stream.erb

@@ -0,0 +1,7 @@
+<% target = @navigation_item.parent ? dom_id(@navigation_item.parent, :children) : 'navigation_items' %>
+<%= turbo_stream.append target,
+                      partial: 'better_together/navigation_items/navigation_item_row',
+                      locals: { item: @navigation_item } %>
+<%= turbo_stream.replace 'flash_messages',
+                         partial: 'layouts/better_together/flash_messages',
+                         locals: { flash: } %>

app/views/better_together/navigation_items/destroy.turbo_stream.erb

@@ -0,0 +1,4 @@
+<%= turbo_stream.remove dom_id(@navigation_item) %>
+<%= turbo_stream.replace 'flash_messages',
+                         partial: 'layouts/better_together/flash_messages',
+                         locals: { flash: } %>