feat(storybook): refine manager layout and Hanmac branding

.storybook/manager.css

@@ -65,6 +65,8 @@
   padding: 0;
   color: var(--color-fg-on-green-primary);
 }
+/* The Settings button is hidden, so the title uses the full header width. */
+#storybook-sidebar-region .sidebar-header > div { margin-right: 0; }
 #storybook-sidebar-region .sidebar-header > div a {
   color: var(--color-fg-on-green-primary);
   font: 700 16px/30px var(--hm-manager-font);
@@ -103,6 +105,10 @@
 }
 /* Storybook's named creation action only; search/filter remain available. */
 #storybook-sidebar-region button[aria-label='Create a new story'] { display: none; }
+/* Storybook Settings menu trigger only; sidebar search, tag filter and expand/collapse remain. */
+#storybook-sidebar-region .sidebar-header button[aria-label='Settings'] { display: none; }
+/* Storybook sidebar search landmark (input, icon, shortcut hint, tag filter); the tree and header remain. */
+#storybook-sidebar-region [role='search'] { display: none; }
 
 #storybook-explorer-tree .sidebar-subheading {
   position: relative;