fix(#2358): scope review.md and ship.md temp files to a per-run mktemp directory (#2433)

* fix(#2358): scope review workflow temp files to a per-run mktemp dir

/gsd-review wrote every prompt/section/output temp file to a hardcoded
/tmp path keyed only on the phase number, so two GSD projects sharing
a small phase number collide on the exact same path and a crashed
run's leftover file becomes bait a later, unrelated run can silently
read. ship.md's external peer-review stderr capture was strictly
worse — one shared, unqualified path across every project/phase/run.

Thread a single mktemp -d "${TMPDIR:-/tmp}/gsd-review.XXXXXX" run
directory through every review.md temp path (67 sites) via a new
{run_dir}/$RUN_DIR placeholder, mirroring the existing {phase}
substitution mechanism, and clean it up at the end of the run. Route
ship.md's stderr capture through a per-run mktemp file the same way.

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

* chore(#2358): regenerate fixtures + lint gate-prep

* fix(#2358): repair failing tests after gate verification

* fix(#2358): thread RUN_DIR scoping into reviewer-instances.md (#1517)

review.md's own invoke_reviewers step lazily loads
gsd-core/references/reviewer-instances.md for the review.reviewer_instances
codepath, but that doc was missed when review.md and ship.md were moved to
the run-scoped {run_dir} temp directory. It still read the combined prompt
from the old /tmp/gsd-review-prompt-{phase}.md (which build_prompt no longer
writes, breaking reviewer-instances functionality outright) and wrote each
instance's output to the old unscoped /tmp/gsd-review-${INSTANCE_NAME}-{phase}.md,
leaving the exact cross-project temp-file collision bug open for that code
path. Both paths now thread through {run_dir}, matching every other reviewer
block in review.md.

Extends the existing #2358 regression test with assertions pinning
reviewer-instances.md's prompt read and output write to {run_dir}, and adds
the Fixed changeset fragment. Regenerated the golden-install-parity content
hashes for reviewer-instances.md via `npm run gen:golden` (paths unchanged;
only the modified file's hash moved).

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

* chore(#2358): backfill changeset pr (#2433)

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

tests/workflow-size-baseline.json

@@ -64,14 +64,14 @@
   "remove-phase.md": 8513,
   "remove-workspace.md": 7551,
   "resume-project.md": 17270,
-  "review.md": 50362,
+  "review.md": 50497,
   "scan.md": 7732,
   "secure-phase.md": 13622,
   "session-report.md": 4044,
   "settings-advanced.md": 40019,
   "settings-integrations.md": 15892,
   "settings.md": 33467,
-  "ship.md": 25222,
+  "ship.md": 25555,
   "sketch-wrap-up.md": 14267,
   "sketch.md": 20004,
   "smart-entry.md": 11124,