[diffusion] feat: support loading serialized comfy w4a8 checkpoints (#36036)

docs/cookbook/diffusion/MiniMax/MiniMax-H3.mdx

@@ -298,6 +298,14 @@ layers in their original dtype, and reuses SRT's MXFP8 dense kernels. The
 selected SRT backend must support MXFP8 on the target GPU; FSDP is rejected for
 this mixed per-layer layout.
 
+W4A8 ConvRot DiT files use the same flagless flow. With
+`comfy-kitchen>=0.2.27`, pass a file such as
+`starsfriday/MiniMax-H3-w4a8/minimax_h3_fl2va_pruned_w4a8_mixed.safetensors`
+to `--transformer-weights-path`; SGLang reads the serialized per-layer metadata
+and packed INT4 tensors automatically. Do not add `--quantization`. TP remains
+subject to each row-parallel shard preserving the checkpoint's ConvRot group
+boundary, and FSDP is rejected.
+
 ### Advanced: precomputed AdaLN cache
 
 The [model card](https://huggingface.co/MiniMaxAI/MiniMax-H3) notes that about

docs/docs/sglang-diffusion/quantization.mdx

@@ -184,6 +184,14 @@ backend.
       <td>SRT's platform MXFP8 backend</td>
       <td>Serialized metadata is auto-detected. NVIDIA and ROCm reuse SRT's dense MXFP8 kernels; Ascend keeps its native online path. Mixed per-layer checkpoints do not support FSDP.</td>
     </tr>
+    <tr>
+      <td><code>comfy-w4a8-convrot</code></td>
+      <td>Safetensors with serialized <code>asym_w4a8_int8</code> layer metadata and packed weights</td>
+      <td><code>--transformer-weights-path</code></td>
+      <td>MiniMax-H3 FL2VA / Ref2VA DiTs</td>
+      <td><code>comfy-kitchen&gt;=0.2.27</code></td>
+      <td>Auto-detected; omit <code>--quantization</code>. Requires SM80+ and validates packed weights, group/channel scales, and optional codebooks before model construction. TP must preserve ConvRot group boundaries; offload is supported and FSDP is not.</td>
+    </tr>
     <tr>
       <td><code>qvg-kv</code></td>
       <td>Unquantized model with runtime causal KV-cache compression</td>