fix(op-supernode): error on uninitialized chain sync status (ethereum-optimism#19543)

* fix(op-supernode): error on uninitialized chain sync status

* fix(op-supernode): use SyncStatus() in FinalizedL2Head to get nil guard

FinalizedL2Head was calling c.vn.SyncStatus() directly, bypassing the
nil guard added in SyncStatus(). This would panic if the virtual node
hadn't been initialized yet.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: opsuperchain <opsuperchain@slop.bot>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

op-supernode/supernode/chain_container/chain_container.go

@@ -364,7 +364,7 @@ func (c *simpleChainContainer) SyncStatus(ctx context.Context) (*eth.SyncStatus,
 		if c.log != nil {
 			c.log.Warn("SyncStatus: virtual node not initialized")
 		}
-		return &eth.SyncStatus{}, nil
+		return nil, virtual_node.ErrVirtualNodeNotRunning
 	}
 	st, err := c.vn.SyncStatus(ctx)
 	if err != nil {

op-supernode/supernode/chain_container/chain_container_test.go

@@ -1166,3 +1166,18 @@ func TestChainContainer_LocalSafeBlockAtTimestamp(t *testing.T) {
 		})
 	}
 }
+
+func TestChainContainer_SyncStatus_UninitializedVirtualNode(t *testing.T) {
+	t.Parallel()
+
+	chainID := eth.ChainIDFromUInt64(420)
+	log := createTestLogger(t)
+	cfg := createTestCLIConfig(t.TempDir())
+	initOverload := &rollupNode.InitializationOverrides{}
+
+	container := NewChainContainer(chainID, createTestVNConfig(), log, cfg, initOverload, nil, nil, nil)
+
+	status, err := container.SyncStatus(context.Background())
+	require.Nil(t, status)
+	require.ErrorIs(t, err, virtual_node.ErrVirtualNodeNotRunning)
+}

op-supernode/supernode/chain_container/super_authority.go

@@ -56,7 +56,7 @@ func (c *simpleChainContainer) FinalizedL2Head() (eth.BlockID, bool) {
 		return eth.BlockID{}, true
 	}
 
-	ss, err := c.vn.SyncStatus(context.Background())
+	ss, err := c.SyncStatus(context.Background())
 	if err != nil {
 		c.log.Error("FinalizedL2Head: failed to get sync status", "err", err)
 		return eth.BlockID{}, true