Fix KeyError when prompt entries lack class_type key (#12595)

Skip entries in the prompt dict that don't contain a class_type key
in apply_replacements(), preventing crashes on metadata or non-node
entries.

Fixes Comfy-Org/ComfyUI#12517

app/node_replace_manager.py

@@ -46,6 +46,8 @@ class NodeReplaceManager:
         connections: dict[str, list[tuple[str, str, int]]] = {}
         need_replacement: set[str] = set()
         for node_number, node_struct in prompt.items():
+            if "class_type" not in node_struct or "inputs" not in node_struct:
+                continue
             class_type = node_struct["class_type"]
             # need replacement if not in NODE_CLASS_MAPPINGS and has replacement
             if class_type not in nodes.NODE_CLASS_MAPPINGS.keys() and self.has_replacement(class_type):