chore🔧: move to go-admin-core v2

Every import of the module changes, not only the seven packages that
moved out of sdk/pkg: Go requires the major version in the path from v2
on. Both happen in one pass —

    go run github.com/go-admin-team/go-admin-core/tools/coreupgrade@v2.0.0 -w -v2 .
    go mod tidy

— which is the command the release notes give, run here as a consumer
would run it. 210 imports across 95 files.

The compatibility shims this used are gone in v2, so the paths that
moved had to move: sdk/pkg/captcha, sdk/pkg/jwtauth and its user
package, sdk/pkg/response and sdk/pkg/casbin.

The count of unformatted files is unchanged at 34, none of them touched
by this: the tool reformats a file only if it was already gofmt clean,
so a migration cannot disappear into whitespace.

app/admin/service/sys_menu.go

@@ -5,7 +5,7 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/go-admin-team/go-admin-core/sdk/pkg"
+	"github.com/go-admin-team/go-admin-core/v2/sdk/pkg"
 	"github.com/pkg/errors"
 	"gorm.io/gorm"
 
@@ -14,7 +14,7 @@ import (
 	cDto "go-admin/common/dto"
 	cModels "go-admin/common/models"
 
-	"github.com/go-admin-team/go-admin-core/sdk/service"
+	"github.com/go-admin-team/go-admin-core/v2/sdk/service"
 )
 
 type SysMenu struct {