[matrixarkai]

The full Rust workflow stopped while building the optional backend because raft-proto could not find protoc. Install protobuf-compiler alongside the existing system build dependencies in both Rust jobs so the append report can build on a fresh runner.

Validation: parsed the workflow, checked both installation scripts with bash syntax validation, and confirmed the local protobuf compiler is available. No Rust source or dependency versions changed. The full hosted run will validate the runner setup.

Please review before merging.

[matrixarkai]

Superseded: main already installs protobuf-compiler in the CI build steps (4 occurrences in rust-ci.yml, landed with #2391), so the remaining delta here is two comment lines. Closing rather than merging a conflicting no-op; reopen if the comments are wanted on their own.

[matrixarkai]

Narrowing the remaining delta, since only one of the two comment lines is still worth having: the other one is a grammar fix, and the text it corrects is live on main at rust-ci.yml:129 — # This example requires the optional backend and are skipped by default builds. The second line here (The optional backend also builds raft-proto, which invokes protoc.) is covered by the longer note #2391 added above the install step.

Not worth a full CI run on its own; worth folding into the next change that touches this file.