Integrate backend APIs and move review to center editor tab

src/core/ApiHttpClient.js

@@ -0,0 +1,23 @@
+export class ApiHttpClient {
+  constructor(baseUrl = null) {
+    const envBase = window.__API_BASE_URL__ || null;
+    this.baseUrl = (baseUrl || envBase || "http://localhost:8081").replace(/\/$/, "");
+  }
+
+  async request(path, options = {}) {
+    const response = await fetch(`${this.baseUrl}${path}`, {
+      ...options,
+      headers: {
+        "Content-Type": "application/json",
+        ...(options.headers || {})
+      }
+    });
+    const isJson = (response.headers.get("content-type") || "").includes("application/json");
+    const body = isJson ? await response.json() : null;
+    if (!response.ok) {
+      const desc = body?.desc || body?.detail || `HTTP ${response.status}`;
+      throw new Error(desc);
+    }
+    return body;
+  }
+}