fix(build): use ubuntu:26.04 base image to match llama-server glibc

Signed-off-by: Dorin Geman <dorin.geman@docker.com>

Author: doringeman

Makefile

@@ -3,7 +3,7 @@ APP_NAME := model-runner
 GO_VERSION := 1.25.8
 LLAMA_SERVER_VERSION := latest
 LLAMA_SERVER_VARIANT := cpu
-BASE_IMAGE := ubuntu:24.04
+BASE_IMAGE := ubuntu:26.04
 VLLM_BASE_IMAGE := nvidia/cuda:13.0.2-runtime-ubuntu24.04
 VLLM_VERSION ?= 0.17.0
 DOCKER_IMAGE := docker/model-runner:latest