[Feature] Add LoRA support for embedding layers (#14177)

Co-authored-by: Baizhou Zhang <sobereddiezhang@gmail.com>
Co-authored-by: Beichen-Ma <bm685@cornell.edu>

python/sglang/srt/layers/logits_processor.py

@@ -837,7 +837,10 @@ class LogitsProcessor(nn.Module):
             )
             dp_gather_replicate(hidden_states, local_hidden_states, logits_metadata)
 
-        if hasattr(lm_head, "weight"):
+        if hasattr(lm_head, "set_lora") and hasattr(lm_head, "apply_lora"):
+            # This is a LoRA-wrapped module, use its forward method
+            logits = lm_head(hidden_states)
+        elif hasattr(lm_head, "weight"):
             if self.use_fp32_lm_head:
                 logits = torch.matmul(
                     hidden_states.to(torch.float32), lm_head.weight.to(torch.float32).T