chore(docker): try pip install flash-attn fallback when wheel tag mismatches

Dockerfile

@@ -73,7 +73,8 @@ RUN if [ "$INSTALL_FLASH_ATTN" = "true" ]; then \
         echo "Installing flash-attn from $FLASH_ATTN_WHEEL_URL" && \
         pip install --no-cache-dir "$FLASH_ATTN_WHEEL_URL"; \
       else \
-        echo "flash-attn wheel tag mismatch for $PYTAG. Skipping flash-attn install. Override FLASH_ATTN_WHEEL_URL if needed."; \
+        echo "flash-attn wheel tag mismatch for $PYTAG. Trying pip install flash-attn (no-build-isolation)." && \
+        (pip install --no-cache-dir --no-build-isolation flash-attn || echo "flash-attn pip install failed; continuing without flash-attn"); \
       fi; \
     else \
       echo "Skipping flash-attn installation"; \