refactor(auth): delegate access control to be-system

Remove Agent Desk users, roles, login sessions, tokens, and local permission persistence. Expose the backend as an embeddable ai-agent module with host-provided subject lookup and operation authorization callbacks, and complete the frontend/backend repository split.

internal/pkg/enums/enums.go

@@ -57,32 +57,3 @@ func IsValidGender(gender int) bool {
 	}
 	return false
 }
-
-type ThirdProvider string
-
-const (
-	ThirdProviderWxWork   ThirdProvider = "wxwork"
-	ThirdProviderDingtalk ThirdProvider = "dingtalk"
-	ThirdProviderOIDC     ThirdProvider = "oidc"
-)
-
-var ThirdProviderValues = []ThirdProvider{ThirdProviderWxWork, ThirdProviderDingtalk, ThirdProviderOIDC}
-
-var thirdProviderLabelMap = map[ThirdProvider]string{
-	ThirdProviderWxWork:   "企业微信",
-	ThirdProviderDingtalk: "钉钉",
-	ThirdProviderOIDC:     "OIDC",
-}
-
-func GetThirdProviderLabel(provider ThirdProvider) string {
-	return thirdProviderLabelMap[provider]
-}
-
-func IsValidThirdProvider(provider string) bool {
-	for _, p := range ThirdProviderValues {
-		if string(p) == provider {
-			return true
-		}
-	}
-	return false
-}