feat(video): suppress metadata PNG + silent intermediate by default

Upstream VHS writes 3 files per render when audio is connected:
  - <name>_NNNNN.png      (first-frame sidecar with workflow metadata)
  - <name>_NNNNN.mov      (silent intermediate)
  - <name>_NNNNN-audio.mov (final audio-muxed video)

Both extras are controlled by hidden VHS_MetadataImage and
VHS_KeepIntermediate flags in extra_pnginfo['workflow']['extra'],
both default-on upstream. Result: a single 500MB render lands as
three files (one needed, two clutter), nearly 2x the disk footprint
and a confusing folder.

Adds two optional BOOLEAN inputs (both default False on Koolook):
  - save_metadata_png
  - keep_silent_intermediate

combine_video injects them into extra_pnginfo before delegating to
super(), so the existing upstream flags do the actual work — no
post-hoc file deletion, no fork divergence from upstream's encoder
path. The extra_pnginfo dict is copied (not mutated in place) so
other nodes in the workflow that reference the same dict are
unaffected.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

k_video_combine.py

@@ -228,6 +228,20 @@ if _VHS_AVAILABLE:
                     "tooltip": "Auto-create the output directory if missing.",
                 },
             )
+            types["optional"]["save_metadata_png"] = (
+                "BOOLEAN",
+                {
+                    "default": False,
+                    "tooltip": "Save the first-frame PNG with embedded workflow metadata.",
+                },
+            )
+            types["optional"]["keep_silent_intermediate"] = (
+                "BOOLEAN",
+                {
+                    "default": False,
+                    "tooltip": "Keep the audio-less intermediate video when audio is muxed in.",
+                },
+            )
             return types
 
         def combine_video(self, *args, **kwargs):
@@ -243,6 +257,23 @@ if _VHS_AVAILABLE:
                 kwargs.pop("output_directory", "")
             )
             create_path_if_missing = kwargs.pop("create_path_if_missing", False)
+            save_metadata_png = kwargs.pop("save_metadata_png", False)
+            keep_silent_intermediate = kwargs.pop("keep_silent_intermediate", False)
+
+            # Inject VHS's hidden extra_options flags so upstream skips
+            # the metadata PNG and deletes the silent intermediate after
+            # audio mux. Defaults are False on Koolook (one clean file
+            # per render); flip the toggles to re-enable upstream's
+            # default-on behavior. Copy extra_pnginfo before mutating so
+            # other nodes referencing the same dict aren't affected.
+            extra_pnginfo = dict(kwargs.get("extra_pnginfo") or {})
+            workflow = dict(extra_pnginfo.get("workflow") or {})
+            extra = dict(workflow.get("extra") or {})
+            extra["VHS_MetadataImage"] = bool(save_metadata_png)
+            extra["VHS_KeepIntermediate"] = bool(keep_silent_intermediate)
+            workflow["extra"] = extra
+            extra_pnginfo["workflow"] = workflow
+            kwargs["extra_pnginfo"] = extra_pnginfo
 
             # Split-mode: directory + name combined into one effective
             # prefix that the existing isabs discrimination handles