feat: add Pivoine custom ComfyUI nodes for DiffRhythm

Add custom node wrapper PivoineDiffRhythmRun that fixes tensor dimension
mismatch error by disabling chunked VAE decoding. The original DiffRhythm
node's overlap=32 parameter conflicts with the VAE's 64-channel architecture.

Changes:
- Add comfyui/nodes/pivoine_diffrhythm.py: Custom node wrapper
- Add comfyui/nodes/__init__.py: Package initialization
- Add arty.yml setup/pivoine-nodes: Deployment script for symlink
- Update all 4 DiffRhythm workflows to use PivoineDiffRhythmRun

Technical details:
- Inherits from DiffRhythmRun to avoid upstream patching
- Forces chunked=False in diffrhythmgen() override
- Requires more VRAM (~12-16GB) but RTX 4090 has 24GB
- Category: 🌸Pivoine/Audio for easy identification

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

comfyui/nodes/__init__.py

@@ -0,0 +1,20 @@
+"""
+Pivoine Custom ComfyUI Nodes
+Custom node extensions and wrappers for RunPod deployment
+
+Author: valknar@pivoine.art
+"""
+
+from .pivoine_diffrhythm import NODE_CLASS_MAPPINGS as DIFFRHYTHM_MAPPINGS
+from .pivoine_diffrhythm import NODE_DISPLAY_NAME_MAPPINGS as DIFFRHYTHM_DISPLAY
+
+# Combine all node mappings
+NODE_CLASS_MAPPINGS = {
+    **DIFFRHYTHM_MAPPINGS,
+}
+
+NODE_DISPLAY_NAME_MAPPINGS = {
+    **DIFFRHYTHM_DISPLAY,
+}
+
+__all__ = ['NODE_CLASS_MAPPINGS', 'NODE_DISPLAY_NAME_MAPPINGS']

comfyui/nodes/pivoine_diffrhythm.py

@@ -0,0 +1,69 @@
+"""
+Pivoine DiffRhythm Node
+Custom wrapper for DiffRhythm that disables chunked decoding to prevent
+tensor dimension mismatch errors (32 vs 64) in VAE overlap logic.
+
+Author: valknar@pivoine.art
+"""
+
+import sys
+sys.path.append('/workspace/ComfyUI/custom_nodes/ComfyUI_DiffRhythm')
+
+from DiffRhythmNode import DiffRhythmRun
+
+class PivoineDiffRhythmRun(DiffRhythmRun):
+    """
+    Pivoine version of DiffRhythmRun with chunked decoding disabled.
+
+    Changes from original:
+    - chunked parameter defaults to False (was True)
+    - Prevents tensor dimension mismatch in VAE
+    - Requires more VRAM (~12-16GB) but works reliably on RTX 4090
+    """
+
+    CATEGORY = "🌸Pivoine/Audio"
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return super().INPUT_TYPES()
+
+    def diffrhythmgen(
+        self,
+        edit,
+        model: str,
+        style_prompt: str = None,
+        lyrics_or_edit_lyrics: str = "",
+        style_audio_or_edit_song = None,
+        edit_segments: str = "",
+        chunked: bool = False,  # Changed from True to False
+        odeint_method: str = "euler",
+        steps: int = 30,
+        cfg: int = 4,
+        quality_or_speed: str = "speed",
+        unload_model: bool = False,
+        seed: int = 0
+    ):
+        # Force chunked=False to avoid dimension mismatch
+        return super().diffrhythmgen(
+            edit=edit,
+            model=model,
+            style_prompt=style_prompt,
+            lyrics_or_edit_lyrics=lyrics_or_edit_lyrics,
+            style_audio_or_edit_song=style_audio_or_edit_song,
+            edit_segments=edit_segments,
+            chunked=False,
+            odeint_method=odeint_method,
+            steps=steps,
+            cfg=cfg,
+            quality_or_speed=quality_or_speed,
+            unload_model=unload_model,
+            seed=seed
+        )
+
+NODE_CLASS_MAPPINGS = {
+    "PivoineDiffRhythmRun": PivoineDiffRhythmRun,
+}
+
+NODE_DISPLAY_NAME_MAPPINGS = {
+    "PivoineDiffRhythmRun": "Pivoine DiffRhythm Run",
+}

comfyui/workflows/text-to-music/diffrhythm-full-length-t2m-v1.json

@@ -4,7 +4,7 @@
   "nodes": [
     {
       "id": 1,
-      "type": "DiffRhythmRun",
+      "type": "PivoineDiffRhythmRun",
       "pos": [100, 100],
       "size": [400, 400],
       "flags": {},

comfyui/workflows/text-to-music/diffrhythm-random-generation-v1.json

@@ -4,7 +4,7 @@
   "nodes": [
     {
       "id": 1,
-      "type": "DiffRhythmRun",
+      "type": "PivoineDiffRhythmRun",
       "pos": [100, 100],
       "size": [400, 400],
       "flags": {},

comfyui/workflows/text-to-music/diffrhythm-reference-based-v1.json

@@ -27,7 +27,7 @@
     },
     {
       "id": 2,
-      "type": "DiffRhythmRun",
+      "type": "PivoineDiffRhythmRun",
       "pos": [500, 100],
       "size": [400, 450],
       "flags": {},

comfyui/workflows/text-to-music/diffrhythm-simple-t2m-v1.json

@@ -4,7 +4,7 @@
   "nodes": [
     {
       "id": 1,
-      "type": "DiffRhythmRun",
+      "type": "PivoineDiffRhythmRun",
       "pos": [100, 100],
       "size": [400, 400],
       "flags": {},