Feature: embedded layout mode and schedule improvements

- Add layout-embedded class for nested entity selectors
- Simplified styling for embedded widgets (less padding, borders)
- Schedule toggle row with summary badges
- Summary badges show datetime range, weekly schedule, holiday count
- Flag fallback styling for countries without valid ISO codes
- Section hint margin after embedded entity selector
- Holiday countries group without modifiers section

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sources/scss/components/_schedule.scss

@@ -306,3 +306,64 @@
         border-radius: $es-radius-lg;
     }
 }
+
+// Schedule toggle row (form-content layout)
+.schedule-toggle-row {
+    display: flex;
+    align-items: center;
+    background: $es-slate-100;
+    border: 1px solid $es-border-color;
+    border-radius: $es-radius-lg;
+
+    .schedule-toggle-switch {
+        padding: $es-spacing-sm $es-spacing-md;
+    }
+
+    .schedule-toggle-actions {
+        padding: $es-spacing-sm $es-spacing-md;
+        border-left: 1px solid $es-border-color;
+        cursor: pointer;
+        transition: background-color $es-transition-fast;
+
+        &:hover {
+            background: $es-slate-200;
+        }
+
+        .material-icons {
+            color: $es-slate-400;
+            font-size: 20px;
+        }
+    }
+}
+
+// Schedule summary badges (read-only indicators in header)
+.schedule-summary-badges {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    margin-left: auto;
+    padding: 0 $es-spacing-sm;
+}
+
+.schedule-badge {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.25rem;
+    padding: 0.25rem 0.5rem;
+    background: $es-slate-200;
+    color: $es-slate-600;
+    font-size: $es-font-size-xs;
+    font-weight: $es-font-weight-medium;
+    border-radius: $es-radius-full;
+    white-space: nowrap;
+
+    .material-icons {
+        font-size: 14px;
+        opacity: 0.7;
+    }
+}
+
+// Section hint after embedded entity selector - add margin
+.schedule-holidays .section-hint {
+    margin-top: $es-spacing-md;
+}