同步完整源码至远程：扁平化重构现状 + 未入库源文件

- 补入库：server/internal/db/dump.go、redis 分页/扫描预算测试、opsxdb-mcp main_test、
  packages/opsxdb-mcp package-lock、docs 审计与对比文档等 37 个新文件
- 含结构扁平化进行中的 80 处修改与 155 处旧结构删除（server/ src/ src-tauri/ 为当前有效源）
- 构建产物（bin/target/dist）与签名私钥仍按规则排除

server/internal/db/mysql.go

@@ -152,7 +152,7 @@ func listColumnsMySQL(ctx context.Context, db *sql.DB, database, table string) (
 		if err := rows.Scan(&field, &typ, &collation, &null, &key, &def, &extra, &priv, &comment); err != nil {
 			return nil, err
 		}
-		col := ColumnInfo{Name: field, Type: typ, Nullable: null == "YES", Key: key, Comment: comment.String}
+		col := ColumnInfo{Name: field, Type: typ, Nullable: null == "YES", Key: key, Comment: comment.String, Extra: extra.String}
 		if def.Valid {
 			col.Default = def.String
 		}