fix(frontend): isolate administration rail from portal CSS

frontend/src/index.css

@@ -181,6 +181,21 @@
  * Scoped so it never leaks into widgets.
  */
 @layer components {
+  /* Omics Portal and Thoth share one document in the embedded deployment.
+     Keep rail geometry on product-specific class names so Hyper/Bootstrap's
+     global spacing utilities (for example .px-4 !important) cannot resize it. */
+  .thot-session-navigation__header {
+    padding: 1.25rem 1rem 0.75rem;
+  }
+
+  .thot-session-navigation__primary-controls {
+    display: flex;
+    min-width: 0;
+    flex-direction: column;
+    gap: 0.5rem;
+    padding: 0 1rem 0.75rem;
+  }
+
   /* Standard micro-label: panel headers, nav sections, meta rows. Set in the
      mono register so labels/meta read as a distinct typographic layer from the
      sans body prose (mono needs less tracking than the sans did). */