feat(metadata): persist parent image lineage

metadata_utils.py

@@ -397,6 +397,7 @@ def build_imh_metadata(params: dict, workflow_json: dict) -> dict:
         "vae": params.get('vae_name', ''),
         "denoise": params.get('denoise', 1.0),
         "generation_type": params.get('generation_type'),
+        "parent_image": _sanitize(params.get('parent_image')),
         "source_image": _sanitize(params.get('source_image')),
         "width": params['width'],
         "height": params['height'],

metahub_save_node.py

@@ -198,6 +198,9 @@ class MetaHubSaveNode:
             prompt_data = prompt if isinstance(prompt, dict) else workflow_json.get("prompt", {})
             if not isinstance(prompt_data, dict):
                 prompt_data = {}
+            parent_image = None
+            if isinstance(extra_pnginfo, dict):
+                parent_image = extra_pnginfo.get("parent_image")
 
             workflow_json = utils.ensure_prompt_in_workflow(workflow_json, prompt_data)
             save_node_id = str(unique_id) if unique_id is not None else None
@@ -309,6 +312,7 @@ class MetaHubSaveNode:
                 "project_name": project_name,
                 "lora_list": lora_list,
                 "lora_hashes": lora_hashes,
+                "parent_image": parent_image,
                 "generation_type": extracted.get("generation_type"),
                 "source_image": extracted.get("source_image"),
                 # Performance metrics (Tier 1, 2, 3)

tests/test_metadata_utils.py

@@ -147,6 +147,7 @@ def test_build_imh_metadata_includes_workflow_and_prompt():
         "height": 768,
         "lora_list": [],
         "generation_type": "img2img",
+        "parent_image": {"fileName": "selected.png", "relativePath": "library/selected.png"},
         "source_image": {"fileName": "base.png", "relativePath": "inputs/base.png"},
     }
     workflow_json = {"workflow": {"nodes": []}, "prompt": {"1": {"class_type": "KSampler"}}}
@@ -157,6 +158,7 @@ def test_build_imh_metadata_includes_workflow_and_prompt():
     assert imh["workflow"] == workflow_json["workflow"]
     assert imh["prompt_api"] == workflow_json["prompt"]
     assert imh["generation_type"] == "img2img"
+    assert imh["parent_image"]["fileName"] == "selected.png"
     assert imh["source_image"]["fileName"] == "base.png"