No concrete merge-blocking issues found in the PR diff.

I checked the workspace wiring, proto paths, build.rs generation setup, exported Rust module, and git diff --check passed. I could not run cargo check -p orb-pcp-messages or buf lint in this sandbox because the environment is read-only and lacks buf/protoc, so CI should cover those checks.

No concrete correctness, security, or regression issues found in the PR diff.

I could not fully verify locally: cargo check was blocked by the read-only sandbox trying to write Cargo/rustup cache state, and buf is not installed in this environment.

No concrete merge-blocking issues found in the PR diff.

I could not run cargo check -p orb-pcp-messages or buf lint in this sandbox because rustup cannot write to its home directory here, and protoc/buf are not installed. Static review only.

I found no concrete merge-blocking issues in the PR diff.

I could not run full verification in this environment: cargo check hit a read-only rustup temp path, and buf/protoc are not installed outside the Nix shell here.

No concrete merge-blocking issues found in the PR diff.

I couldn’t execute the new crate tests here because the read-only environment prevented rustup from creating temp files under /home/runner/.rustup; buf also isn’t installed in this runner. The schema/build wiring looks consistent with the workspace and CI’s nix develop setup.

I found no concrete merge-blocking issues in the changes introduced by this PR.

Note: I couldn’t run the Rust checks locally because this sandbox is read-only/offline for the required toolchain/dependencies, so this is a static review of the diff.

No concrete merge-blocking issues found in the PR diff.

I reviewed the new proto definitions, Rust prost crate wiring, workspace inclusion, and Proto CI workflow. I wasn’t able to run the Rust/buf checks locally in this read-only environment, so this is a static review.

No concrete issues found in the PR changes.

I attempted CARGO_TARGET_DIR=/tmp/orb-pcp-defs-target cargo test -p orb-pcp-defs, but this sandbox’s read-only rustup home prevented running tests locally. Existing Rust CI should still cover the new workspace crate.

No concrete issues found in the PR-introduced changes. The new proto definitions, Rust wrapper crate, workspace registration, and Buf CI wiring look consistent with the existing workspace setup. I did not run the Rust tests because the workspace is read-only in this environment.

No concrete merge-blocking issues found in the PR diff.

I could not run cargo metadata or tests because the environment is read-only and rustup failed creating a temp file under /home/runner/.rustup/tmp. The static review covered the added proto schema, Rust build wrapper, tests, workspace wiring, and proto CI workflow.

No concrete merge-blocking issues found in the PR diff.

Static review covered the new proto schema, Rust prost crate wiring, workspace registration, tests, and the new buf CI workflow. I could not run cargo check locally because rustup attempted to write under read-only /home/runner/.rustup.

Found one concrete issue:

• pcp-defs/rust/tests/round_trip.rs:44: DiIrisEmbeddingShareV1 is constructed without the new embedding_version field defined in di_iris_embedding_shares.proto. Since prost generates plain Rust structs with required fields in struct literals, cargo nextest run --workspace --all-features --all-targets should fail to compile this test. Add embedding_version: "...".into(), to the initializer.

I did not find other merge-blocking issues in the PR diff.

No concrete blocking issues found in the PR diff. The new protobuf definitions, Rust wrapper crate, tests, workspace entry, and proto lint/format CI look consistent with the existing repo patterns.