feat: add workflow run dispatch foundation

backend/app/domains/rendering/workflow_router.py

@@ -200,6 +200,9 @@ async def list_workflow_runs(
 
 
 class WorkflowDispatchResponse(BaseModel):
+    workflow_run: WorkflowRunOut
+    context_id: str
+    execution_mode: str
     dispatched: int
     task_ids: list[str]
 
@@ -225,7 +228,15 @@ async def dispatch_workflow_endpoint(
     the caller can track progress.
     """
     from pydantic import ValidationError as _ValidationError
-    from app.domains.rendering.workflow_executor import dispatch_workflow
+    from app.domains.rendering.workflow_executor import (
+        dispatch_prepared_workflow,
+        prepare_workflow_context,
+    )
+    from app.domains.rendering.workflow_run_service import (
+        apply_graph_dispatch_result,
+        create_workflow_run,
+        mark_workflow_run_failed,
+    )
 
     result = await db.execute(
         select(WorkflowDefinition).where(WorkflowDefinition.id == workflow_id)
@@ -237,10 +248,59 @@ async def dispatch_workflow_endpoint(
         raise HTTPException(status_code=400, detail="Workflow has no config")
 
     try:
-        task_ids = dispatch_workflow(wf.config, context_id)
+        workflow_context = prepare_workflow_context(
+            wf.config,
+            context_id=context_id,
+            execution_mode="graph",
+        )
     except _ValidationError as exc:
         raise HTTPException(status_code=422, detail=f"Invalid workflow config: {exc.errors()}")
     except ValueError as exc:
         raise HTTPException(status_code=422, detail=str(exc))
 
-    return WorkflowDispatchResponse(dispatched=len(task_ids), task_ids=task_ids)
+    run_id = await db.run_sync(
+        lambda sync_session: create_workflow_run(
+            sync_session,
+            workflow_def_id=wf.id,
+            order_line_id=None,
+            workflow_context=workflow_context,
+        ).id
+    )
+    await db.commit()
+
+    try:
+        dispatch_result = dispatch_prepared_workflow(workflow_context)
+    except Exception as exc:
+        failed_result = await db.execute(
+            select(WorkflowRun)
+            .where(WorkflowRun.id == run_id)
+            .options(selectinload(WorkflowRun.node_results))
+        )
+        failed_run = failed_result.scalar_one()
+        mark_workflow_run_failed(failed_run, str(exc))
+        await db.commit()
+        raise
+
+    run_result = await db.execute(
+        select(WorkflowRun)
+        .where(WorkflowRun.id == run_id)
+        .options(selectinload(WorkflowRun.node_results))
+    )
+    run = run_result.scalar_one()
+    apply_graph_dispatch_result(run, workflow_context, dispatch_result)
+    await db.commit()
+
+    refreshed_result = await db.execute(
+        select(WorkflowRun)
+        .where(WorkflowRun.id == run_id)
+        .options(selectinload(WorkflowRun.node_results))
+    )
+    refreshed_run = refreshed_result.scalar_one()
+
+    return WorkflowDispatchResponse(
+        workflow_run=refreshed_run,
+        context_id=context_id,
+        execution_mode=workflow_context.execution_mode,
+        dispatched=len(dispatch_result.task_ids),
+        task_ids=dispatch_result.task_ids,
+    )