chore(CI): bump PyTorch from 2.7 to 2.8 (#4884)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Chores**
* Upgraded PyTorch to 2.8 across CPU and CUDA 12.x environments for
improved compatibility and stability.
* Updated development container to download the matching LibTorch 2.8
CPU bundle.
* Refreshed CI pipelines (build, test, analysis) to install and validate
against PyTorch 2.8.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Jinzhe Zeng <njzjz@qq.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: njzjz

.devcontainer/download_libtorch.sh

@@ -4,5 +4,5 @@ set -ev
 SCRIPT_PATH=$(dirname $(realpath -s $0))
 cd ${SCRIPT_PATH}/..
 
-wget https://download.pytorch.org/libtorch/cpu/libtorch-cxx11-abi-shared-with-deps-2.7.0%2Bcpu.zip -O ~/libtorch.zip
+wget https://download.pytorch.org/libtorch/cpu/libtorch-cxx11-abi-shared-with-deps-2.8.0%2Bcpu.zip -O ~/libtorch.zip
 unzip ~/libtorch.zip

.github/workflows/build_cc.yml

@@ -33,7 +33,7 @@ jobs:
     - uses: lukka/get-cmake@latest
     - run: python -m pip install uv
     - run: source/install/uv_with_retry.sh pip install --system tensorflow
-    - run: source/install/uv_with_retry.sh pip install --system 'torch==2.7' --index-url https://download.pytorch.org/whl/cpu
+    - run: source/install/uv_with_retry.sh pip install --system 'torch==2.8.*' --index-url https://download.pytorch.org/whl/cpu
     - run: |
          wget https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2204/x86_64/cuda-keyring_1.0-1_all.deb \
          && sudo dpkg -i cuda-keyring_1.0-1_all.deb \

.github/workflows/codeql.yml

@@ -41,7 +41,7 @@ jobs:
          && sudo apt-get update \
          && sudo apt-get -y install cuda-cudart-dev-12-2 cuda-nvcc-12-2
         python -m pip install tensorflow
-        python -m pip install 'torch==2.7' --index-url https://download.pytorch.org/whl/cpu
+        python -m pip install 'torch==2.8.*' --index-url https://download.pytorch.org/whl/cpu
       env:
         DEBIAN_FRONTEND: noninteractive
     # Initializes the CodeQL tools for scanning.

.github/workflows/test_cc.yml

@@ -28,7 +28,7 @@ jobs:
         source/install/uv_with_retry.sh pip install --system tensorflow-cpu~=2.18.0 jax==0.5.0
         export TENSORFLOW_ROOT=$(python -c 'import importlib.util,pathlib;print(pathlib.Path(importlib.util.find_spec("tensorflow").origin).parent)')
         source/install/uv_with_retry.sh pip install --system -e .[cpu,test,lmp,jax] mpi4py mpich
-        source/install/uv_with_retry.sh pip install --system 'torch==2.7' --index-url https://download.pytorch.org/whl/cpu
+        source/install/uv_with_retry.sh pip install --system 'torch==2.8.*' --index-url https://download.pytorch.org/whl/cpu
     - name: Convert models
       run: source/tests/infer/convert-models.sh
     # https://github.com/actions/runner-images/issues/9491

backend/find_pytorch.py

@@ -116,7 +116,7 @@ def get_pt_requirement(pt_version: str = "") -> dict:
         cuda_version = os.environ.get("CUDA_VERSION", "12.2")
         if cuda_version == "" or cuda_version in SpecifierSet(">=12,<13"):
             # CUDA 12.2, cudnn 9
-            pt_version = "2.7.0"
+            pt_version = "2.8.0"
         elif cuda_version in SpecifierSet(">=11,<12"):
             # CUDA 11.8, cudnn 8
             pt_version = "2.3.1"