fix(ci): build llama-helper sidecar before Rust tests in PR Checks - #17

Description

Fixes the PR Checks workflow failure on main (run 32168196009, commit 969c3ca).

The Rust (test) job failed at the Run Rust tests step (cargo test in frontend/src-tauri) because Tauri's build script requires the llama-helper sidecar at binaries/llama-helper-x86_64-unknown-linux-gnu, which was not present.

resource path `binaries/llama-helper-x86_64-unknown-linux-gnu` doesn't exist

Other Linux workflows (e.g. build-linux.yml) already build and copy this binary before compiling the Tauri app. PR Checks was missing that step.

This PR adds a Build llama-helper sidecar step before cargo test, matching the existing Linux build workflow.

Related Issue

Triggered by failed workflow run on main at 969c3ca7c847f69036a34ccba3d4ffae77a5c942.

Type of Change

• Bug fix
• New feature
• Documentation update
• Performance improvement
• Code refactoring
• Other (please describe)

Testing

• Unit tests added/updated
• Manual testing performed
• All tests pass

Verified the failing command and root cause from CI logs. Local full cargo test was not run in the cloud agent environment (git dependency resolution issue unrelated to this change); CI should validate on merge.

Verification command (matches CI Rust job):

cargo build --release -p llama-helper
mkdir -p frontend/src-tauri/binaries
cp target/release/llama-helper frontend/src-tauri/binaries/llama-helper-x86_64-unknown-linux-gnu
cd frontend/src-tauri && cargo test

Documentation

• Documentation updated
• No documentation needed

Checklist

• Code follows project style
• Self-reviewed the code
• Added comments for complex code
• Updated README if needed
• Branch is up to date with devtest
• No merge conflicts

Additional Notes

Classification: Test/CI configuration only (.github/workflows/pr-ci.yml).

Other failures on the same SHA: Multiple Dependabot Updates runs also failed (@blocknote/react unknown_error). Those are separate from PR Checks and were not addressed in this PR.