fix: restore inline diagram controls and synchronize portal theme

scripts/inline-viewer.css

@@ -0,0 +1,32 @@
+/* Portal integration only; keep the upstream renderer and export code pinned. */
+html[data-embed="true"] .toolbar {
+  display: flex !important;
+  position: relative;
+  inset: auto;
+  justify-content: center;
+  height: 52px;
+  padding: 4px;
+  box-sizing: border-box;
+  background: var(--bg);
+}
+html[data-embed="true"] #btn-present,
+html[data-embed="true"] #btn-motion { display: none !important; }
+html[data-embed="true"] .diagram-container > svg {
+  max-height: calc(100vh - 68px);
+}
+html[data-embed="true"] .toolbar .preset-menu,
+html[data-embed="true"] .toolbar .export-menu {
+  position: absolute;
+  top: 100%;
+  left: 0;
+  right: auto;
+  width: min(320px, 100vw);
+  max-width: 100vw;
+  max-height: calc(100vh - 52px);
+  overflow-y: auto;
+  box-sizing: border-box;
+}
+html[data-embed="true"] .toolbar .export-wrap { position: static; }
+html[data-embed="true"] .toolbar .export-menu { left: auto; right: 0; }
+html[data-embed="true"] .toolbar .preset-menu button,
+html[data-embed="true"] .toolbar .export-menu button { min-height: 44px; }