Convert DAG nodes dict to steps list in get_run_plan()

The CLI expects {"steps": [...]} but DAG format stores {"nodes": {...}}.
Added _dag_to_steps() to convert between formats, including topological
sorting so sources appear first.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/services/run_service.py

@@ -512,6 +512,56 @@ class RunService:
 
         return True, None
 
+    def _dag_to_steps(self, dag: Dict[str, Any]) -> Dict[str, Any]:
+        """Convert DAG nodes dict format to steps list format.
+
+        DAG format: {"nodes": {"id": {...}}, "output_id": "..."}
+        Steps format: {"steps": [{"id": "...", "type": "...", ...}], "output_id": "..."}
+        """
+        if "steps" in dag:
+            # Already in steps format
+            return dag
+
+        if "nodes" not in dag:
+            return dag
+
+        nodes = dag.get("nodes", {})
+        steps = []
+
+        # Sort by topological order (sources first, then by input dependencies)
+        def get_level(node_id: str, visited: set = None) -> int:
+            if visited is None:
+                visited = set()
+            if node_id in visited:
+                return 0
+            visited.add(node_id)
+            node = nodes.get(node_id, {})
+            inputs = node.get("inputs", [])
+            if not inputs:
+                return 0
+            return 1 + max(get_level(inp, visited) for inp in inputs)
+
+        sorted_ids = sorted(nodes.keys(), key=lambda nid: (get_level(nid), nid))
+
+        for node_id in sorted_ids:
+            node = nodes[node_id]
+            steps.append({
+                "id": node_id,
+                "step_id": node_id,
+                "type": node.get("node_type", "EFFECT"),
+                "config": node.get("config", {}),
+                "inputs": node.get("inputs", []),
+                "name": node.get("name"),
+                "cache_id": node_id,  # In code-addressed system, node_id IS the cache_id
+            })
+
+        return {
+            "steps": steps,
+            "output_id": dag.get("output_id"),
+            "metadata": dag.get("metadata", {}),
+            "format": "json",
+        }
+
     async def get_run_plan(self, run_id: str) -> Optional[Dict[str, Any]]:
         """Get execution plan for a run.
 
@@ -535,8 +585,7 @@ class RunService:
                         return {"sexp": content, "format": "sexp"}
                     else:
                         plan = json.loads(content)
-                        plan["format"] = "json"
+                        return self._dag_to_steps(plan)
-                        return plan
 
         # Fall back to legacy plans directory
         sexp_path = self.cache_dir / "plans" / f"{run_id}.sexp"
@@ -548,8 +597,7 @@ class RunService:
         if json_path.exists():
             with open(json_path) as f:
                 plan = json.load(f)
-                plan["format"] = "json"
+                return self._dag_to_steps(plan)
-                return plan
 
         return None