[DREAM-803] Show blankslate on empty filter

Applies the dynamic empty-state lifecycle to the project life cycle
and project attributes settings lists, replacing the detached
plain-text no-results notice.

https://community.openproject.org/wp/DREAM-803

Author: myabc

app/components/projects/settings/life_cycle/index_component.html.erb

@@ -26,7 +26,8 @@
         OpenProject::Common::BorderBoxListComponent.new(
           container: "project-life-cycle-administration",
           position: :relative,
-          mb: 3
+          mb: 3,
+          empty_state_behavior: :dynamic
         )
       ) do |list|
         list.with_header(title: I18n.t("projects.settings.life_cycle.section_header")) do |header|
@@ -75,15 +76,5 @@
         list.with_empty_state(title: t("projects.settings.life_cycle.non_defined"))
       end
     end
-    flex.with_row do
-      render Primer::Beta::Text.new(
-        display: :none,
-        data: {
-          "projects--settings--border-box-filter-target": "noResultsText"
-        }
-      ) do
-        I18n.t("js.autocompleter.notFoundText")
-      end
-    end
   end
 %>

app/components/projects/settings/project_custom_field_sections/show_component.html.erb

@@ -5,6 +5,7 @@
         container: "project-custom-field-section-#{@project_custom_field_section.id}",
         position: :relative,
         mb: 3,
+        empty_state_behavior: :dynamic,
         classes: "op-project-custom-field-section",
         test_selector: "project-custom-field-section-#{@project_custom_field_section.id}"
       )

spec/features/projects/project_custom_fields/settings/mapping_spec.rb

@@ -364,6 +364,47 @@
       end
     end
 
+    it "shows each section's own blankslate when the filter matches nothing, and restores rows on clear" do
+      visit project_settings_project_custom_fields_path(project)
+
+      fill_in "border-box-filter", with: "no such attribute exists"
+
+      [section_for_input_fields, section_for_select_fields, section_for_multi_select_fields].each do |section|
+        within_custom_field_section_container(section) do
+          expect(page).to have_css(
+            "[data-empty-list-item='true']",
+            text: I18n.t("settings.project_attributes.label_no_project_custom_fields")
+          )
+        end
+      end
+
+      # Cuprite's Node#set clears a field's existing value without firing an
+      # `input` event before it types the replacement characters, so setting
+      # `with: ""` never reaches the border-box-filter Stimulus controller.
+      # Backspacing through the native key-event path (like a real user
+      # clearing the field) does fire `input` on every keystroke — but the
+      # field must be (re-)focused first, since Node#set blurs it afterwards.
+      filter_field = find_field("border-box-filter")
+      filter_field.click
+      clear_input_field_contents(filter_field)
+
+      within_custom_field_section_container(section_for_input_fields) do
+        expect(page).to have_no_css("[data-empty-list-item]")
+        expect(page).to have_content("Boolean field")
+        expect(page).to have_content("String field")
+      end
+
+      within_custom_field_section_container(section_for_select_fields) do
+        expect(page).to have_no_css("[data-empty-list-item]")
+        expect(page).to have_content("List field")
+      end
+
+      within_custom_field_section_container(section_for_multi_select_fields) do
+        expect(page).to have_no_css("[data-empty-list-item]")
+        expect(page).to have_content("Multi list field")
+      end
+    end
+
     it "shows the project custom field sections in the correct order" do
       visit project_settings_project_custom_fields_path(project)