[Doc] Refine Diffusion Tutorial Documents (#1305)

Signed-off-by: Didan Deng <33117903+wtomin@users.noreply.github.com>

docs/contributing/model/adding_diffusion_model.md

@@ -1,4 +1,4 @@
-# Adding a Diffusion Model to vLLM-Omni
+# Adding a Diffusion Model
 
 This guide walks you through adding a new diffusion model to vLLM-Omni. We use **Qwen-Image** as the primary example, with references to other models (LongCat, Flux, Wan2.2) to illustrate different patterns.
 
@@ -680,7 +680,7 @@ vLLM-Omni automatically compiles blocks in `_repeated_blocks` when `torch.compil
 
 ### Tensor Parallelism
 
-See detailed guide: [How to add Tensor Parallel support](../features/tensor_parallel.md)
+See detailed guide: [How to add Tensor Parallel support](../../design/feature/tensor_parallel.md)
 
 **Quick setup:**
 
@@ -694,7 +694,7 @@ omni = Omni(model="your-model", tensor_parallel_size=2)
 
 ### CFG Parallelism
 
-See detailed guide: [How to add CFG-Parallel support](../features/cfg_parallel.md)
+See detailed guide: [How to add CFG-Parallel support](../../design/feature/cfg_parallel.md)
 
 **Quick setup:**
 
@@ -708,7 +708,7 @@ omni = Omni(model="your-model", cfg_parallel_size=2)
 
 ### Sequence Parallelism
 
-See detailed guide: [How to add Sequence Parallel support](../features/sequence_parallel.md)
+See detailed guide: [How to add Sequence Parallel support](../../design/feature/sequence_parallel.md)
 
 **Quick setup:**
 
@@ -724,7 +724,7 @@ omni = Omni(model="your-model", ulysses_degree=2, ring_degree=2)
 
 #### TeaCache
 
-See detailed guide: [How to add TeaCache support](../features/teacache.md)
+See detailed guide: [How to add TeaCache support](../../design/feature/teacache.md)
 
 **Quick setup:**
 
@@ -744,7 +744,7 @@ omni = Omni(model="your-model",
 
 #### Cache-DiT
 
-See detailed guide: [How to add Cache-DiT support](../features/cache_dit.md)
+See detailed guide: [How to add Cache-DiT support](../../design/feature/cache_dit.md)
 
 **Quick setup:**