feat: Page Editor UX Phase 2 - unsaved changes panel, property search, reset property, empty states

- ProjectEditorFacade.resetField(key): field-level revert-to-original, reusing getByPath + a new immutable setByPath (write-side counterpart, scalar/object dot-paths only).
- app-form-field gains showReset/resetLabel/(resetClicked) - a reusable per-field reset affordance, wired on branding logo/title and theme primary/background color.
- Save bar: unsaved-changes count is now clickable, expanding a field-level diff list (reuses facade.changeSummary(), already built for the Preview tab) with jump-to-section links.
- BuilderPropertySearchComponent: filters EditorSchemaService.all() by translated label/hint, jumps to the owning section - no new registry, reuses the existing schema.
- navigation-section: app-empty-state (existing component) added for empty header/footer link lists.
- Reset Section and Draft/Published badge were already implemented; not touched.
- New copy added as translation keys (en/ru/hy).

src/app/shared/ui/form-field/form-field.component.html

@@ -1,11 +1,19 @@
 <div class="app-form-field">
   @if (label()) {
-    <label class="app-form-field__label" [for]="fieldId">
-      {{ label() }}
-      @if (required()) {
-        <span class="app-form-field__required" aria-hidden="true">*</span>
+    <div class="app-form-field__label-row">
+      <label class="app-form-field__label" [for]="fieldId">
+        {{ label() }}
+        @if (required()) {
+          <span class="app-form-field__required" aria-hidden="true">*</span>
+        }
+      </label>
+      @if (showReset()) {
+        <button type="button" class="app-form-field__reset" [attr.aria-label]="resetLabel()" (click)="resetClicked.emit()">
+          <app-icon name="refresh" [size]="12" />
+          {{ resetLabel() }}
+        </button>
       }
-    </label>
+    </div>
   }
 
   <div class="app-form-field__control">

src/app/shared/ui/form-field/form-field.component.scss

@@ -4,12 +4,40 @@
   gap: var(--space-xs, 0.25rem);
 }
 
+.app-form-field__label-row {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--space-sm, 0.5rem);
+}
+
 .app-form-field__label {
   font-size: var(--font-size-base, 0.875rem);
   font-weight: var(--font-weight-semibold, 600);
   color: var(--text-primary, #1f322d);
 }
 
+.app-form-field__reset {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.2rem;
+  border: none;
+  background: none;
+  padding: 0;
+  color: var(--text-secondary, #6b7280);
+  font-size: var(--font-size-xs, 0.75rem);
+  cursor: pointer;
+
+  &:hover {
+    color: var(--primary-color, #2f6e5d);
+  }
+
+  &:focus-visible {
+    outline: 2px solid var(--primary-color, #2f6e5d);
+    outline-offset: 2px;
+  }
+}
+
 .app-form-field__required {
   color: var(--error-color, #c0392b);
   margin-left: 0.125rem;

src/app/shared/ui/form-field/form-field.component.ts

@@ -1,4 +1,5 @@
-import { ChangeDetectionStrategy, Component, computed, input } from '@angular/core';
+import { ChangeDetectionStrategy, Component, computed, input, output } from '@angular/core';
+import { IconComponent } from '../icon/icon.component';
 
 let nextFormFieldId = 0;
 
@@ -14,6 +15,7 @@ export abstract class FormFieldContext {
 @Component({
   selector: 'app-form-field',
   standalone: true,
+  imports: [IconComponent],
   templateUrl: './form-field.component.html',
   styleUrl: './form-field.component.scss',
   changeDetection: ChangeDetectionStrategy.OnPush,
@@ -27,6 +29,10 @@ export class FormFieldComponent implements FormFieldContext {
   /** Optional "Where is this used?" list, e.g. ['Buttons', 'Links', 'Badges']. Already-translated strings. */
   readonly usedBy = input<readonly string[] | null>(null);
   readonly usedByLabel = input<string | null>(null);
+  /** Shows a small "reset to original" button next to the label when the field has been changed. */
+  readonly showReset = input(false);
+  readonly resetLabel = input<string | null>(null);
+  readonly resetClicked = output<void>();
 
   readonly fieldId = `app-form-field-${++nextFormFieldId}`;
   protected readonly hintId = `${this.fieldId}-hint`;