Remove circuit structure preview

src/app/globals.css

@@ -305,35 +305,6 @@ a.kpi:hover {
   min-width: 8rem;
 }
 
-.circuit-tree-table .section-row td {
-  background: #e9eef8;
-  border-top: 2px solid #c6d3ea;
-  font-weight: 600;
-}
-
-.circuit-tree-table .summary-row td {
-  background: #f5f8fd;
-  font-weight: 600;
-}
-
-.circuit-tree-table .device-row td {
-  background: #ffffff;
-}
-
-.circuit-tree-table .reserve-row td {
-  background: #f8fbff;
-}
-
-.circuit-tree-table .placeholder-row td {
-  background: #f7f7f7;
-  color: #6c757d;
-  font-style: italic;
-}
-
-.circuit-tree-table .indented-cell {
-  padding-left: 1.5rem;
-}
-
 .tree-editor-shell {
   display: flex;
   flex-direction: column;

src/app/projects/[projectId]/circuit-lists/[circuitListId]/tree-edit/page.tsx

@@ -15,12 +15,6 @@ export default function CircuitTreeEditPage() {
           <p className="text-secondary mb-0">Stromkreise und zugeordnete Geräte bearbeiten.</p>
         </div>
         <div className="d-flex gap-2">
-          <Link
-            href={`/projects/${params.projectId}/circuit-lists/${params.circuitListId}/tree`}
-            className="btn btn-outline-secondary btn-sm"
-          >
-            Strukturvorschau
-          </Link>
           <Link href={`/projects/${params.projectId}`} className="btn btn-outline-secondary btn-sm">
             Zum Projekt
           </Link>

src/app/projects/[projectId]/circuit-lists/[circuitListId]/tree/page.tsx

@@ -1,38 +0,0 @@
-"use client";
-
-import Link from "next/link";
-import { useParams } from "next/navigation";
-import { CircuitTreePreview } from "../../../../../../frontend/components/circuit-tree-preview";
-
-export default function CircuitTreePreviewPage() {
-  const params = useParams<{ projectId: string; circuitListId: string }>();
-  const projectId = params.projectId;
-  const circuitListId = params.circuitListId;
-
-  return (
-    <main className="container py-4">
-      <div className="d-flex justify-content-between align-items-center mb-3">
-        <div>
-          <h1 className="h4 mb-1">Vorschau der Stromkreisstruktur</h1>
-          <p className="text-secondary mb-0">
-            Schreibgeschützte Vorschau der Bereiche, Stromkreise und Gerätezeilen.
-          </p>
-        </div>
-        <Link
-          href={`/projects/${projectId}/circuit-lists/${circuitListId}/tree-edit`}
-          className="btn btn-outline-primary btn-sm"
-        >
-          Editor öffnen
-        </Link>
-        <Link
-          href={`/projects/${projectId}`}
-          className="btn btn-outline-secondary btn-sm"
-        >
-          Zum Projekt
-        </Link>
-      </div>
-
-      <CircuitTreePreview projectId={projectId} circuitListId={circuitListId} />
-    </main>
-  );
-}