Function evaluate_layer2 

pub fn evaluate_layer2(
    project_root: &Path,
    phase: u32,
    git_flow: &GitFlowConfig,
    stage: Stage,
) -> Result<Option<AgentResult>, ResultError>

Layer 2: Use exit code + commit count to determine result.

Reads exit code from .devflow/phase-NN-exit file. Counts commits in feature/phase-NN branch (if it exists).

The commit-count gate (“no commits → failed”) is scoped to stage — it only applies to Stage::Plan/Stage::Code (checked via an explicit matches!, NOT Stage::is_agent_stage(), since that also includes Define, which legitimately produces zero commits). exit≠0 is ALWAYS Failed, for every stage — only the exit=0/zero-commits branch is stage-scoped.

Decision matrix: exit≠0 → Failed (ALL stages) exit=0, stage in {Plan, Code}, commits=0 → Failed (“no work done”) exit=0, stage in {Plan, Code}, commits>0 → Success exit=0, stage NOT in {Plan, Code} (Define/Validate/Ship), commits=0 → Success (not commit-gated; Validate’s real pass signal is its verdict, not a bare zero-commit — see Task 2’s turn.completed deferral) exit unknown → fall to Layer 3 (return None)

WR-06 (13-REVIEW.md): takes only the explicit project_root parameter for both the .devflow/ file paths and the git subprocess current_dir — previously it also accepted state: &State and used state.project_root for the git calls, which every caller happened to pass consistently with project_root but which the function itself had no way to enforce.