[management] Persist peer flags in meta updates (#3958)

This PR adds persistence for peer feature flags when updating metadata, including equality checks, gRPC extraction, and corresponding unit tests.

- Introduce a new `Flags` struct with `isEqual` and incorporate it into `PeerSystemMeta`.
- Update `UpdateMetaIfNew` logic to consider flag changes.
- Extend gRPC server’s `extractPeerMeta` to populate `Flags` and add tests for `Flags.isEqual`.

management/server/peer/peer_test.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"net/netip"
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 // FQDNOld is the original implementation for benchmarking purposes
@@ -83,3 +85,59 @@ func TestIsEqual(t *testing.T) {
 		t.Error("meta1 should be equal to meta2")
 	}
 }
+
+func TestFlags_IsEqual(t *testing.T) {
+	tests := []struct {
+		name   string
+		f1     Flags
+		f2     Flags
+		expect bool
+	}{
+		{
+			name: "should be equal when all fields are identical",
+			f1: Flags{
+				RosenpassEnabled: true, RosenpassPermissive: false, ServerSSHAllowed: true,
+				DisableClientRoutes: false, DisableServerRoutes: true, DisableDNS: false,
+				DisableFirewall: true, BlockLANAccess: false, BlockInbound: true, LazyConnectionEnabled: true,
+			},
+			f2: Flags{
+				RosenpassEnabled: true, RosenpassPermissive: false, ServerSSHAllowed: true,
+				DisableClientRoutes: false, DisableServerRoutes: true, DisableDNS: false,
+				DisableFirewall: true, BlockLANAccess: false, BlockInbound: true, LazyConnectionEnabled: true,
+			},
+			expect: true,
+		},
+		{
+			name: "shouldn't be equal when fields are different",
+			f1: Flags{
+				RosenpassEnabled: true, RosenpassPermissive: false, ServerSSHAllowed: true,
+				DisableClientRoutes: false, DisableServerRoutes: true, DisableDNS: false,
+				DisableFirewall: true, BlockLANAccess: false, BlockInbound: true, LazyConnectionEnabled: true,
+			},
+			f2: Flags{
+				RosenpassEnabled: false, RosenpassPermissive: true, ServerSSHAllowed: false,
+				DisableClientRoutes: true, DisableServerRoutes: false, DisableDNS: true,
+				DisableFirewall: false, BlockLANAccess: true, BlockInbound: false, LazyConnectionEnabled: false,
+			},
+			expect: false,
+		},
+		{
+			name:   "should be equal when both are empty",
+			f1:     Flags{},
+			f2:     Flags{},
+			expect: true,
+		},
+		{
+			name:   "shouldn't be equal when at least one field differs",
+			f1:     Flags{RosenpassEnabled: true},
+			f2:     Flags{RosenpassEnabled: false},
+			expect: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			require.Equal(t, tt.expect, tt.f1.isEqual(tt.f2))
+		})
+	}
+}