fix(serializer): preserve block enabled state during deserialization

The deserializer hardcodes `enabled: true` for regular blocks,
ignoring the `enabled` field that was correctly saved during
serialization. This causes disabled blocks to silently become
re-enabled when a workflow is loaded, imported, or round-tripped
through serialize/deserialize.

The loop/parallel branch already handles this correctly with
`serializedBlock.enabled ?? true` — apply the same pattern to
regular blocks.

Author: lawrence3699

apps/sim/serializer/index.ts

@@ -622,7 +622,7 @@ export class Serializer {
       position: serializedBlock.position,
       subBlocks,
       outputs: serializedBlock.outputs,
-      enabled: true,
+      enabled: serializedBlock.enabled ?? true,
       triggerMode:
         serializedBlock.config?.params?.triggerMode === true ||
         serializedBlock.metadata?.category === 'triggers',