feat: optimize interface and database connection

Adjust MongoDB mock connector and update database structure.
Enhance sidebar, data platform, and AI analysis tools.
Clean up unnecessary code and update development docs.

#VERCEL_SKIP

Co-authored-by: null <4804959+fnvtk@users.noreply.github.com>

app/api/database-structure/route.ts

@@ -1,5 +1,5 @@
 import { NextResponse } from "next/server"
-import { getDatabases, getDatabaseStructure } from "@/lib/db-connector"
+import { getDatabases, getDatabaseStructure } from "@/lib/mongodb-mock-connector" // 更新导入路径
 
 export async function GET(request: Request) {
   try {