Update Rust toolchain version in CI workflows and add .rust-toolchain file

.github/workflows/linux-release-build.yml

@@ -91,7 +91,7 @@ jobs:
       - name: Fix Rust version
         run: |
           # Install a rust version compatible with LLVM 18
-          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain 1.79
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain $(cat .rust-toolchain)
           source $HOME/.cargo/env
 
           if test "${{ matrix.arch }}" = "aarch64"; then

.github/workflows/macos-release-build.yml

@@ -82,7 +82,7 @@ jobs:
 
           brew install watchman
 
-          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain 1.79
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain $(cat .rust-toolchain)
           source $HOME/.cargo/env
 
           if test "${{ matrix.arch }}" = "aarch64"; then

.github/workflows/windows-release-build.yml

@@ -176,14 +176,14 @@ jobs:
       - name: Setup Rust
         if: ${{ !(inputs.generate-gpo && matrix.arch == 'aarch64') }}
         run: |
-          cd engine/
-          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain 1.81
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain $(cat .rust-toolchain)
           source $HOME/.cargo/env
           if test "${{ matrix.arch }}" = "aarch64"; then
             rustup target add aarch64-pc-windows-msvc
           else
             rustup target add x86_64-pc-windows-msvc
           fi
+          cd engine/
           cargo install cargo-download --locked
           cargo download -x windows=0.58.0
           export CARGO_INCREMENTAL=0

.rust-toolchain

@@ -0,0 +1 @@
+1.82