feat(oidc): 支持自定义 OIDC 登录显示名称 (#6012)

* docs: add design spec for OIDC custom display name

Mirrors the existing Custom OAuth Provider name pattern so admins can
show a meaningful label instead of the hardcoded "OIDC" on the login
page and in related copy.

* feat(oidc): add configurable display name with OIDC fallback

* feat(oidc): use configured display name in provider name and status API

* feat(oidc): add display name field to default-theme OIDC settings

Claude-Session: https://claude.ai/code/session_01FDkWJqigJi9yE3HG5pjZP5

* feat(oidc): show configured display name on default-theme login button

* feat(oidc): add display name field to classic-theme OIDC settings

* feat(oidc): show configured display name on classic-theme login button

* fix(oidc): trim whitespace before applying display name fallback

* chore: remove internal design doc from PR

Design/planning docs are working artifacts for this session and
shouldn't be submitted to the upstream project.

* fix(oidc): lead with example in classic-theme display name placeholder

Reorders the combined placeholder to show the example first, then
the fallback note, matching the Custom OAuth Provider Name field's
placeholder convention (example-only) that this feature mirrors.

* fix(i18n): improve Russian grammar in OIDC display-name placeholder translation

Leads each clause with its condition/subject and adds the missing
verb, per PR review feedback.

* test(web): remove redundant OIDC harness tests

controller/misc.go

@@ -111,6 +111,7 @@ func GetStatus(c *gin.Context) {
 		"oidc_enabled":                system_setting.GetOIDCSettings().Enabled,
 		"oidc_client_id":              system_setting.GetOIDCSettings().ClientId,
 		"oidc_authorization_endpoint": system_setting.GetOIDCSettings().AuthorizationEndpoint,
+		"oidc_display_name":           system_setting.GetOIDCSettings().GetEffectiveDisplayName(),
 		"passkey_login":               passkeySetting.Enabled,
 		"passkey_display_name":        passkeySetting.RPDisplayName,
 		"passkey_rp_id":               passkeySetting.RPID,

controller/misc_oidc_test.go

@@ -0,0 +1,60 @@
+package controller
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/QuantumNous/new-api/common"
+	"github.com/QuantumNous/new-api/setting/system_setting"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetStatusReturnsEffectiveOIDCDisplayName(t *testing.T) {
+	settings := system_setting.GetOIDCSettings()
+	originalDisplayName := settings.DisplayName
+	originalOptionMap := common.OptionMap
+	t.Cleanup(func() {
+		settings.DisplayName = originalDisplayName
+		common.OptionMap = originalOptionMap
+	})
+	common.OptionMap = map[string]string{}
+
+	tests := []struct {
+		name        string
+		displayName string
+		want        string
+	}{
+		{
+			name:        "custom name is trimmed",
+			displayName: "  Acme SSO  ",
+			want:        "Acme SSO",
+		},
+		{
+			name:        "whitespace-only name falls back",
+			displayName: "   ",
+			want:        "OIDC",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			settings.DisplayName = tt.displayName
+			response := httptest.NewRecorder()
+			context, _ := gin.CreateTestContext(response)
+			context.Request = httptest.NewRequest(http.MethodGet, "/api/status", nil)
+
+			GetStatus(context)
+
+			var payload struct {
+				Success bool           `json:"success"`
+				Data    map[string]any `json:"data"`
+			}
+			require.NoError(t, common.Unmarshal(response.Body.Bytes(), &payload))
+			require.True(t, payload.Success)
+			assert.Equal(t, tt.want, payload.Data["oidc_display_name"])
+		})
+	}
+}