fix(management): private-service validation + tunnel-IP lookup semantics

- Require an explicit port for L4 cluster targets. validateL4Target
  exempted TargetTypeCluster from the port check, but buildPathMappings
  serializes every L4 target via net.JoinHostPort(host, port) — port=0
  shipped a ":0" upstream. Cluster targets use the same Host/Port
  fields, so the same requirement applies.
- GetPeerByIP returns NotFound on a tunnel-IP miss instead of mapping
  every error to Internal. The proxy's ValidateTunnelPeer probes IPs
  that legitimately aren't in the roster; the miss is expected and now
  distinguishable from a real store failure.
- Thread ctx into getClusterCapability's gorm query so a cancelled
  request doesn't keep the store busy.

Tests updated for the L4-cluster port requirement and the GetPeerByIP
NotFound path.

management/internals/modules/reverseproxy/service/service.go

@@ -932,7 +932,11 @@ func (s *Service) validateL4Target(target *Target) error {
 	if target.TargetId == "" {
 		return errors.New("target_id is required for L4 services")
 	}
-	if target.TargetType != TargetTypeCluster && target.Port == 0 {
+	// Cluster targets resolve their upstream host:port from the target's
+	// own Host/Port fields just like the other L4 types — buildPathMappings
+	// emits net.JoinHostPort(target.Host, target.Port) for every L4
+	// target, so allowing port=0 here would let ":0" reach the proxy.
+	if target.Port == 0 {
 		return errors.New("target port is required for L4 services")
 	}
 	switch target.TargetType {

management/internals/modules/reverseproxy/service/service_test.go

@@ -1176,7 +1176,12 @@ func TestValidate_HTTPClusterTarget_RequiresDirectUpstream(t *testing.T) {
 	assert.ErrorContains(t, rp.Validate(), "direct upstream disabled", "cluster target must reject direct_upstream=false")
 }
 
-func TestValidate_L4ClusterTarget(t *testing.T) {
+// TestValidate_L4ClusterTarget_RequiresPort confirms that an L4 cluster
+// target without an explicit port is rejected. buildPathMappings emits
+// net.JoinHostPort(target.Host, target.Port) for every L4 target — so
+// allowing port=0 would let the proxy ship ":0" upstreams. The port
+// requirement is the same as every other L4 target type.
+func TestValidate_L4ClusterTarget_RequiresPort(t *testing.T) {
 	rp := validProxy()
 	rp.Mode = ModeTCP
 	rp.ListenPort = 9000
@@ -1186,7 +1191,12 @@ func TestValidate_L4ClusterTarget(t *testing.T) {
 		Protocol:   "tcp",
 		Enabled:    true,
 	}}
-	require.NoError(t, rp.Validate(), "L4 cluster target must validate without an explicit port")
+	assert.ErrorContains(t, rp.Validate(), "port is required",
+		"L4 cluster target must require an explicit port like other L4 target types")
+
+	rp.Targets[0].Port = 5432
+	rp.Targets[0].Host = "db.lan"
+	require.NoError(t, rp.Validate(), "L4 cluster target with host:port must validate")
 }
 
 func TestService_Copy_RoundtripsPrivate(t *testing.T) {

management/server/store/sql_store.go

@@ -4734,7 +4734,13 @@ func (s *SqlStore) GetPeerByIP(ctx context.Context, lockStrength LockingStrength
 	result := tx.
 		Take(&peer, fmt.Sprintf("account_id = ? AND %s = ?", column), accountID, jsonValue)
 	if result.Error != nil {
-		// no logging here
+		// A tunnel-IP miss is an expected outcome (e.g. the proxy's
+		// ValidateTunnelPeer probing an address that isn't in the
+		// account roster); surface it as NotFound so callers can tell
+		// it apart from a real store failure.
+		if errors.Is(result.Error, gorm.ErrRecordNotFound) {
+			return nil, status.Errorf(status.NotFound, "peer with ip %s not found", ip.String())
+		}
 		return nil, status.Errorf(status.Internal, "failed to get peer from store")
 	}
 
@@ -5962,6 +5968,7 @@ func (s *SqlStore) getClusterCapability(ctx context.Context, clusterAddr, column
 	}
 
 	err := s.db.
+		WithContext(ctx).
 		Model(&proxy.Proxy{}).
 		Select("COUNT(CASE WHEN "+column+" IS NOT NULL THEN 1 END) > 0 AS has_capability, "+
 			"COALESCE(MAX(CASE WHEN "+column+" = true THEN 1 ELSE 0 END), 0) = 1 AS any_true").

management/server/store/sql_store_test.go

@@ -491,6 +491,27 @@ func Test_GetAccount(t *testing.T) {
 	})
 }
 
+// TestSqlStore_GetPeerByIP_NotFound pins the not-found semantics the
+// proxy's ValidateTunnelPeer relies on: a tunnel-IP that isn't in the
+// account roster must surface as a NotFound error (not a generic
+// Internal) so callers can distinguish an expected miss from a real
+// store failure. A known IP still resolves.
+func TestSqlStore_GetPeerByIP_NotFound(t *testing.T) {
+	runTestForAllEngines(t, "../testdata/store.sql", func(t *testing.T, store Store) {
+		const accountID = "bf1c8084-ba50-4ce7-9439-34653001fc3b"
+
+		peer, err := store.GetPeerByIP(context.Background(), LockingStrengthNone, accountID, net.ParseIP("192.168.0.0"))
+		require.NoError(t, err, "known tunnel IP must resolve")
+		require.NotNil(t, peer)
+
+		_, err = store.GetPeerByIP(context.Background(), LockingStrengthNone, accountID, net.ParseIP("100.65.0.99"))
+		require.Error(t, err, "unknown tunnel IP must error")
+		parsedErr, ok := status.FromError(err)
+		require.True(t, ok, "error must be a status error")
+		require.Equal(t, status.NotFound, parsedErr.Type(), "tunnel-IP miss must be NotFound, not Internal")
+	})
+}
+
 func TestSqlStore_SavePeer(t *testing.T) {
 	store, cleanUp, err := NewTestStoreFromSQL(context.Background(), "../testdata/store.sql", t.TempDir())
 	t.Cleanup(cleanUp)