[management, reverse proxy] Add reverse proxy feature (#5291)

* implement reverse proxy


---------

Co-authored-by: Alisdair MacLeod <git@alisdairmacleod.co.uk>
Co-authored-by: mlsmaycon <mlsmaycon@gmail.com>
Co-authored-by: Eduard Gert <kontakt@eduardgert.de>
Co-authored-by: Viktor Liu <viktor@netbird.io>
Co-authored-by: Diego Noguês <diego.sure@gmail.com>
Co-authored-by: Diego Noguês <49420+diegocn@users.noreply.github.com>
Co-authored-by: Bethuel Mmbaga <bethuelmbaga12@gmail.com>
Co-authored-by: Zoltan Papp <zoltan.pmail@gmail.com>
Co-authored-by: Ashley Mensah <ashleyamo982@gmail.com>

proxy/server_test.go

@@ -0,0 +1,48 @@
+package proxy
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDebugEndpointDisabledByDefault(t *testing.T) {
+	s := &Server{}
+	assert.False(t, s.DebugEndpointEnabled, "debug endpoint should be disabled by default")
+}
+
+func TestDebugEndpointAddr(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "empty defaults to localhost",
+			input:    "",
+			expected: "localhost:8444",
+		},
+		{
+			name:     "explicit localhost preserved",
+			input:    "localhost:9999",
+			expected: "localhost:9999",
+		},
+		{
+			name:     "explicit address preserved",
+			input:    "0.0.0.0:8444",
+			expected: "0.0.0.0:8444",
+		},
+		{
+			name:     "127.0.0.1 preserved",
+			input:    "127.0.0.1:8444",
+			expected: "127.0.0.1:8444",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			result := debugEndpointAddr(tc.input)
+			assert.Equal(t, tc.expected, result)
+		})
+	}
+}