[Feature]: FP8 Quantization Support for DiT (#1034)

Signed-off-by: lishunyang <lishunyang12@163.com>
Signed-off-by: SYLAR <125541396+lishunyang12@users.noreply.github.com>

docs/user_guide/diffusion/quantization/overview.md

@@ -0,0 +1,17 @@
+# Quantization for Diffusion Transformers
+
+vLLM-Omni supports quantization of DiT linear layers to reduce memory usage and accelerate inference.
+
+## Supported Methods
+
+| Method | Guide |
+|--------|-------|
+| FP8 | [FP8](fp8.md) |
+
+## Device Compatibility
+
+| GPU Generation | Example GPUs | FP8 Mode |
+|---------------|-------------------|----------|
+| Ada/Hopper (SM 89+) | RTX 4090, H100, H200 | Full W8A8 with native hardware |
+
+Kernel selection is automatic.