Fix autofocus on dynamically inserted forms, remove this.blur() handlers

form_controller.connect() now blurs the previously focused element and
explicitly focuses the [autofocus] element when a form is inserted into
the DOM (via Turbo Stream). Only runs when an [autofocus] element is
present, so closing forms and other stream updates are unaffected.

Remove all onclick='this.blur()' inline handlers from templates — they
were a workaround for the same autofocus problem, now solved properly
via the Stimulus lifecycle.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/views/quantities/_quantity.html.erb

@@ -8,7 +8,7 @@
 
   <td style="--depth:<%= quantity.depth %>">
     <%= link_to quantity, edit_quantity_path(quantity), class: 'link',
-      onclick: 'this.blur();', data: {turbo_stream: true} %>
+      data: {turbo_stream: true} %>
   </td>
   <td><%= quantity.description %></td>
   <td><%= quantity.default_unit&.symbol %></td>
@@ -16,7 +16,7 @@
   <% if current_user.at_least(:active) %>
     <td class="flex">
       <%= image_link_to t('.new_subquantity'), 'plus-outline', new_quantity_path(quantity),
-        id: dom_id(quantity, :new, :link), onclick: 'this.blur();', data: {turbo_stream: true} %>
+        id: dom_id(quantity, :new, :link), data: {turbo_stream: true} %>
 
       <%= image_button_to_if quantity.destroyable?, t('.destroy'), 'delete-outline',
         quantity_path(quantity), method: :delete %>