[Cleanup] Replace bare print() with logger and use specific exception types (#2228)

Signed-off-by: Lidang Jiang <lidangjiang@gmail.com>
Signed-off-by: Lidang-Jiang <lidangjiang@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

vllm_omni/diffusion/diffusion_engine.py

@@ -115,7 +115,7 @@ class DiffusionEngine:
         if output.aborted:
             raise DiffusionRequestAbortedError(output.abort_message or "Diffusion request aborted.")
         if output.error:
-            raise Exception(f"{output.error}")
+            raise RuntimeError(f"{output.error}")
         logger.info("Generation completed successfully.")
 
         if output.output is None: