feat: model composite step inputs

src/wf_core/__init__.py

@@ -1,24 +1,35 @@
 from .models import (
+    ArrayExpression,
     ConditionNode,
     Edge,
     EndNode,
     ForeachConcurrentPolicy,
     ForeachItemErrorPolicy,
     ForeachNode,
+    InputExpression,
+    InputExpressionBinding,
+    InputPathBinding,
+    InputValueBinding,
     InterruptNode,
     JoinNode,
+    JsonValue,
+    LiteralExpression,
     NodeDef,
     NodeResult,
     NodeUse,
+    ObjectExpression,
+    PathExpression,
     ReducerRef,
     ReducerSpec,
     SchemaRef,
     SiblingWritePolicy,
     StateField,
     StateSchema,
+    StepInputBinding,
     SubgraphNode,
     Workflow,
     WorkflowRef,
+    validate_strict_json_value,
     workflow_ref_from,
 )
 from .run_codec import PersistedRunState, dump_run_state, load_run_state
@@ -57,6 +68,7 @@ from .validation import (
 )
 
 __all__ = [
+    "ArrayExpression",
     "END",
     "START",
     "AsyncNodeHandler",
@@ -69,13 +81,21 @@ __all__ = [
     "ForeachNode",
     "FrameStatus",
     "InterruptNode",
+    "InputExpression",
+    "InputExpressionBinding",
+    "InputPathBinding",
+    "InputValueBinding",
     "InterruptRequest",
     "InterruptRoute",
     "JoinNode",
+    "JsonValue",
+    "LiteralExpression",
     "NodeDef",
     "NodeHandler",
     "NodeResult",
     "NodeUse",
+    "ObjectExpression",
+    "PathExpression",
     "PersistedRunState",
     "PreparedSubgraph",
     "ReducerRef",
@@ -87,6 +107,7 @@ __all__ = [
     "SiblingWritePolicy",
     "StateField",
     "StateSchema",
+    "StepInputBinding",
     "StepExecutionResult",
     "SubgraphNode",
     "TraceEntry",
@@ -109,4 +130,5 @@ __all__ = [
     "step_workflow_async",
     "validate_workflow",
     "workflow_ref_from",
+    "validate_strict_json_value",
 ]