[diffusion] Enable LongCat breakable CUDA graphs (#35724)

docs/docs/sglang-diffusion/api/cli.mdx

@@ -207,6 +207,18 @@ For supported native pipelines, set `SGLANG_CACHE_DIT_ENABLED=true` to enable Ca
 
 For supported image pipelines, breakable CUDA graph can be enabled with `--enable-breakable-cuda-graph`, but you must declare every served resolution in `--warmup-resolutions` so warmup captures matching graph signatures.
 
+LongCat-Image is supported by this path. Its DiT always consumes a fixed
+512-token prompt body, so different prompt lengths reuse the same graph without
+model-specific padding. For a 1024x1024 deployment, use:
+
+```bash Command
+sglang serve --model-path meituan-longcat/LongCat-Image \
+  --enable-breakable-cuda-graph \
+  --warmup-resolutions 1024x1024 \
+  --enable-torch-compile false \
+  --port 30010
+```
+
 ### Component Residency
 
 Use `--component-residency COMPONENT=MODE` to assign one runtime residency mode to each native pipeline component: