merge page settings into Page tab and remove Settings tab

Custom page settings (title, slug, meta, published, navigation) now
appear as a collapsible section at the top of the Page tab. The
separate Settings tab has been fully removed.

- Add page_settings_section component to page_renderer.ex
- Remove dead :settings case from editor_panel_content
- Delete settings_editor.ex component entirely
- Remove SettingsEditor import from shop_components.ex
- Add .page-settings-* CSS styles
- Clean up old .settings-* CSS styles

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

assets/css/admin/components.css

@@ -2440,6 +2440,99 @@
   }
 }
 
+/* Page settings section (inline in Page tab for custom pages) */
+
+.page-settings-details {
+  margin-bottom: 0.75rem;
+  border: 1px solid var(--admin-border);
+  border-radius: var(--admin-radius);
+  background: var(--admin-bg-alt);
+}
+
+.page-settings-summary {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  padding: 0.625rem 0.75rem;
+  cursor: pointer;
+  user-select: none;
+  font-size: 0.8125rem;
+  font-weight: 500;
+  color: var(--admin-text-secondary);
+
+  &:hover {
+    color: var(--admin-text-primary);
+  }
+
+  & .page-settings-chevron {
+    margin-left: auto;
+    transition: transform 0.15s ease;
+  }
+}
+
+.page-settings-details[open] .page-settings-chevron {
+  transform: rotate(180deg);
+}
+
+.page-settings-form {
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+  padding: 0 0.75rem 0.75rem;
+}
+
+.page-settings-field {
+  display: flex;
+  flex-direction: column;
+  gap: 0.25rem;
+}
+
+.page-settings-label {
+  font-size: 0.75rem;
+  font-weight: 500;
+  color: var(--admin-text-secondary);
+}
+
+.page-settings-slug-input {
+  display: flex;
+  align-items: center;
+  gap: 0;
+}
+
+.page-settings-slug-prefix {
+  padding: 0.375rem 0.5rem;
+  background: var(--admin-bg);
+  border: 1px solid var(--admin-border);
+  border-right: none;
+  border-radius: var(--admin-radius) 0 0 var(--admin-radius);
+  font-size: 0.875rem;
+  color: var(--admin-text-tertiary);
+}
+
+.page-settings-slug-input .admin-input {
+  border-radius: 0 var(--admin-radius) var(--admin-radius) 0;
+}
+
+.page-settings-checks {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 1rem;
+}
+
+.page-settings-nav-options {
+  display: flex;
+  gap: 0.75rem;
+  padding-left: 1.5rem;
+}
+
+.page-settings-field-inline {
+  flex: 1;
+}
+
+.page-settings-field-sm {
+  width: 5rem;
+}
+
 /* Block list in editor */
 
 .block-list {
@@ -5133,72 +5226,6 @@
 /* Last group in a customise section (no border, tighter margin than theme-group) */
 .theme-group-flush { margin-bottom: 1rem; }
 
-/* ── Settings editor (on-site editor Settings tab) ── */
-
-.settings-editor-form {
-  display: flex;
-  flex-direction: column;
-  gap: 0.25rem;
-}
-
-.settings-slug-preview {
-  display: flex;
-  align-items: center;
-  gap: 0.25rem;
-}
-
-.settings-slug-preview .admin-input {
-  flex: 1;
-}
-
-.settings-nav-options {
-  padding-left: 1rem;
-  border-left: 2px solid var(--admin-border);
-}
-
-.settings-nav-row {
-  display: flex;
-  gap: 0.75rem;
-}
-
-.settings-nav-field {
-  flex: 1;
-}
-
-.settings-nav-field-sm {
-  flex: 0 0 5rem;
-}
-
-.settings-actions {
-  display: flex;
-  align-items: center;
-  gap: 0.75rem;
-  padding-top: 0.5rem;
-}
-
-.settings-save-indicator {
-  display: flex;
-  align-items: center;
-  gap: 0.25rem;
-  font-size: 0.875rem;
-  color: var(--admin-success);
-}
-
-.settings-save-error {
-  color: var(--admin-error);
-}
-
-.settings-admin-link {
-  padding-top: 0.5rem;
-  border-top: 1px solid var(--admin-border);
-}
-
-.settings-info-view {
-  display: flex;
-  flex-direction: column;
-  gap: 0.25rem;
-}
-
 /* ── Content width containers ── */
 
 .admin-content-narrow { max-width: 32rem; }