feat(web): Add org removal functionality to admin user details page (#38013)

Signed-off-by: techknowlogick <techknowlogick@gitea.com>
Signed-off-by: Karthik Bhandary <34509856+karthikbhandary2@users.noreply.github.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.com>
Co-authored-by: bircni <bircni@icloud.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

tests/integration/admin_user_org_test.go

@@ -0,0 +1,53 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"net/http"
+	"testing"
+
+	"gitea.dev/models/organization"
+	"gitea.dev/models/unittest"
+	user_model "gitea.dev/models/user"
+	"gitea.dev/tests"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAdminRemoveUserFromOrg(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+	adminSession := loginUser(t, "user1")
+
+	t.Run("RemoveFromOrg", func(t *testing.T) {
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 4})
+		org := unittest.AssertExistsAndLoadBean(t, &organization.Organization{ID: 3})
+
+		isMember, err := organization.IsOrganizationMember(t.Context(), org.ID, user.ID)
+		assert.NoError(t, err)
+		assert.True(t, isMember)
+
+		req := NewRequest(t, "POST", "/-/admin/users/4/orgs/3/remove")
+		adminSession.MakeRequest(t, req, http.StatusOK)
+
+		isMember, err = organization.IsOrganizationMember(t.Context(), org.ID, user.ID)
+		assert.NoError(t, err)
+		assert.False(t, isMember)
+	})
+
+	t.Run("RemoveFromAllOrg", func(t *testing.T) {
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+
+		orgCount, err := organization.GetOrganizationCount(t.Context(), user)
+		assert.EqualValues(t, 4, orgCount)
+		assert.NoError(t, err)
+		assert.Positive(t, orgCount, "User should be in at least one org")
+
+		req := NewRequest(t, "POST", "/-/admin/users/5/orgs/remove-all")
+		adminSession.MakeRequest(t, req, http.StatusOK)
+
+		orgCountAfter, err := organization.GetOrganizationCount(t.Context(), user)
+		assert.NoError(t, err)
+		assert.EqualValues(t, 2, orgCountAfter) // User 5 is the last owner of remaining orgs
+	})
+}