test(#795): make PR diff fixtures hermetic

Dockerfile.ci

@@ -22,10 +22,10 @@
 FROM node:24-alpine
 
 # Native toolchain required to compile node-gyp deps on musl, plus the
-# postgresql-client used by the test step's pg_isready readiness probe. `bash`
+# postgresql-client used by the test step's pg_isready readiness probe. `bash`,
-# and `git` are baked here too — framework shell tests require both without
+# `git`, and `jq` are baked here too — framework shell tests and the shipped
-# paying for per-run package installation in ci.yml.
+# Codex review wrappers require them without per-run installation in ci.yml.
-RUN apk add --no-cache python3 make g++ postgresql-client bash git
+RUN apk add --no-cache python3 make g++ postgresql-client bash git jq
 
 # Pin pnpm to the repo's packageManager version via corepack.
 RUN corepack enable && corepack prepare pnpm@10.6.2 --activate