Fix CI: use libtorch 2.7.0 to match tch crate expectations

tch v0.20.0 expects PyTorch 2.7.0 exactly. Updated LIBTORCH_VERSION
from 2.7.1 to 2.7.0 and added LIBTORCH_BYPASS_VERSION_CHECK as a
safety net. Also updated build.rs download examples to match.

Signed-off-by: Michael Yuan <michael@secondstate.io>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Michael Yuan <michael@secondstate.io>

Author: juntao

.github/workflows/ci-rust.yml

@@ -10,7 +10,8 @@ jobs:
     timeout-minutes: 120
 
     env:
-      LIBTORCH_VERSION: "2.7.1"
+      LIBTORCH_VERSION: "2.7.0"
+      LIBTORCH_BYPASS_VERSION_CHECK: "1"
 
     steps:
       - uses: actions/checkout@v4

rust/build.rs

@@ -16,13 +16,13 @@ fn main() {
                    export LD_LIBRARY_PATH=$LIBTORCH/lib:$LD_LIBRARY_PATH\n\
                  \n\
                  Example (CPU):\n\
-                   wget https://download.pytorch.org/libtorch/cpu/libtorch-cxx11-abi-shared-with-deps-2.7.1%2Bcpu.zip\n\
-                   unzip libtorch-cxx11-abi-shared-with-deps-2.7.1+cpu.zip\n\
+                   wget https://download.pytorch.org/libtorch/cpu/libtorch-cxx11-abi-shared-with-deps-2.7.0%2Bcpu.zip\n\
+                   unzip libtorch-cxx11-abi-shared-with-deps-2.7.0+cpu.zip\n\
                    export LIBTORCH=$(pwd)/libtorch\n\
                  \n\
                  Example (CUDA 12.8):\n\
-                   wget https://download.pytorch.org/libtorch/cu128/libtorch-cxx11-abi-shared-with-deps-2.7.1%2Bcu128.zip\n\
-                   unzip libtorch-cxx11-abi-shared-with-deps-2.7.1+cu128.zip\n\
+                   wget https://download.pytorch.org/libtorch/cu128/libtorch-cxx11-abi-shared-with-deps-2.7.0%2Bcu128.zip\n\
+                   unzip libtorch-cxx11-abi-shared-with-deps-2.7.0+cu128.zip\n\
                    export LIBTORCH=$(pwd)/libtorch\n\
                  ====================================================="
             );