docs(code-review): changelog + README for run-prefix runner (PLN-1229 Phase 1)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: wongk

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to the claude-plugins project will be documented in this fil
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/). Entries are listed newest-first; each plugin section is treated as released when merged to `main`.
 
+### code-review v3.2.0
+
+#### Added
+- New `run-prefix` helper subcommand: a resumable, in-process runner for the deterministic review prefix (stages `setup` through `cache-check`). It reads `run_plan.json` and walks the stages in one process — resolving each stage's placeholder tokens from prior-stage artifacts, redirecting stdout per stage, and honoring `on_failure` policies and validation gates — instead of one orchestrator turn per stage. It pauses only at genuine decision points (the hygiene-only early exit, a signal-extraction or coverage-critic singleton that needs an agent, or the route/partition boundary), emitting a status JSON that tells the orchestrator what to do next, and resumes from a given stage on re-invocation. A failed `continue_with_coverage_gap` stage emits a canonical `agent-failure` system finding so the gap is auditable. Documented as the `run-prefix` result contract in `SCHEMA.md`.
+- Subprocess A/B parity oracle for the prefix: the golden-fixture harness now walks each fixture two ways — one subprocess per stage (reproducing the current per-stage orchestrator walk) versus the new `run-prefix` runner — and asserts byte-identical normalized artifacts through `cache-check` across all seven fixtures, plus a pause-sequence check pinning the resumable segment boundaries. Contract tests cover token resolution, resumable dependency reconstruction, singleton detection, `on_failure` handling, and the runner's error/boundary returns.
+
 ### code-review v3.1.1
 
 #### Added

plugins/code-review/README.md

@@ -37,7 +37,7 @@ plugins/code-review/
     python/golden_fixture_harness.py     Golden fixture harness: replays canonical inputs through helper subcommands and diffs against expected envelopes (PLN-719 Phase 8)
     python/test_golden_fixtures.py       Pytest driver that runs every fixture under tools/python/fixtures/
     python/fixtures/<name>/              Per-fixture directory (config.yaml + inputs/ + expected/); 3 full scenarios + 6 README-stubs for future coverage
-    python/prefix_golden_harness.py      Prefix golden harness: walks the deterministic prefix (setup→spawn-spec) in-process against real git fixtures and snapshots every intermediate artifact (PLN-1229 Phase 0)
+    python/prefix_golden_harness.py      Prefix golden harness + subprocess A/B parity oracle: walks the deterministic prefix against real git fixtures — in-process for golden snapshots, and per-stage-subprocess vs `run-prefix` for byte-equal parity (PLN-1229 Phase 0/1)
     python/test_prefix_golden.py         Pytest driver for the prefix harness: determinism oracle + golden diff across the prefix_fixtures/ matrix
     python/prefix_fixtures/<name>/       Per-fixture directory (expected/ golden snapshots); 7 branch scenarios (standard, fast-path, hygiene-only, empty-diff, cache-hit, since-last-review, coverage-critic)
 ```
@@ -231,6 +231,7 @@ The helper script is a multi-subcommand Python CLI. The orchestrator invokes it
 | `finalize-result` | Consolidates validated findings + coverage state + verdict into the canonical `review_result.json` envelope; deep-merges `<cr_dir>/telemetry.json` into the canonical `telemetry` block and populates `telemetry.cache_hit_rate["bha"]` from `cache_result.json` (PLN-719 Phase 7/9) |
 | `arbitrate-budget` | Applies the canonical reviewer cap policy; emits coverage gaps for required reviewers that overflow (PLN-719) |
 | `prepare-run` | Emits a declarative `run_plan.json` describing the 30-stage pipeline (PLN-719) |
+| `run-prefix` | Runs the deterministic prefix (setup→cache-check) in one process, resolving tokens and honoring gates/`on_failure`; pauses at the hygiene-only exit, a singleton needing an agent, or the route/partition boundary, emitting a status JSON and resuming from a given stage (PLN-1229) |
 
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