fix(ci): add LLVM to PATH for Windows ARM64 release builds (#487)

The ring crate requires clang for building on Windows ARM64 targets.
Add Visual Studio's bundled LLVM/clang to PATH for the aarch64-pc-windows-msvc
target in the release workflow.

Reference: https://github.com/briansmith/ring/blob/main/BUILDING.md

Co-authored-by: Droid Agent <droid@factory.ai>

Author: echobt

.github/workflows/release.yml

@@ -161,6 +161,30 @@ jobs:
           prefix-key: "rust-release-cli-${{ matrix.target }}"
           shared-key: ${{ needs.prepare.outputs.cache_key }}
 
+      # Windows ARM64 requires clang from Visual Studio for building the ring crate
+      # See: https://github.com/briansmith/ring/blob/main/BUILDING.md
+      - name: Setup LLVM for Windows ARM64
+        if: matrix.target == 'aarch64-pc-windows-msvc'
+        shell: pwsh
+        run: |
+          # Add Visual Studio's LLVM to PATH for ring crate compilation
+          $llvmPath = "C:\Program Files (x86)\Microsoft Visual Studio\2022\Enterprise\VC\Tools\Llvm\x64\bin"
+          if (Test-Path $llvmPath) {
+            echo "Adding LLVM path: $llvmPath"
+            echo "$llvmPath" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+          } else {
+            # Fallback for BuildTools installation
+            $llvmPath = "C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Tools\Llvm\x64\bin"
+            if (Test-Path $llvmPath) {
+              echo "Adding LLVM path (BuildTools): $llvmPath"
+              echo "$llvmPath" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+            } else {
+              echo "WARNING: LLVM path not found. Build may fail."
+              echo "Searching for clang..."
+              Get-ChildItem -Path "C:\Program Files*" -Recurse -Filter "clang.exe" -ErrorAction SilentlyContinue | Select-Object -First 5 | ForEach-Object { echo $_.FullName }
+            }
+          }
+
       - name: Build release binary
         run: cargo +nightly build --release --target ${{ matrix.target }} -p cortex-cli
         env: