fix: csp regressions (#38047)

fix #37257 , all details are in the comments

modules/setting/security_test.go

@@ -0,0 +1,22 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package setting
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoadSecurityFrom(t *testing.T) {
+	cfg, err := NewConfigProviderFromData(`[security]
+X_FRAME_OPTIONS = DENY
+X_CONTENT_TYPE_OPTIONS = unset
+CONTENT_SECURITY_POLICY_GENERAL = "script-src *; foo"`)
+	assert.NoError(t, err)
+	loadSecurityFrom(cfg)
+	assert.Equal(t, "DENY", Security.XFrameOptions)
+	assert.Equal(t, "unset", Security.XContentTypeOptions)
+	assert.Equal(t, `"script-src *`, Security.ContentSecurityPolicyGeneral) // holy shit ini package bug
+}