chore: add stack test base marker

[juliusmarminge]

This disposable PR adds the base marker used to test the stacked pull request workflow.

It creates one inert text file under .github/stack-test. This PR is expected to be closed after the stack test.

Created with GPT-5.6 Sol in the Codex harness.

Summary by CodeRabbit

• Tests
  • Added a sentence to support stacked pull request workflow testing.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Team

Run ID: 57aab6aa-0881-43dd-ad18-01ad0ebbd63d

📥 Commits

Reviewing files that changed from the base of the PR and between e16b8b0 and 5f2f3db.

📒 Files selected for processing (1)

• .github/stack-test/base.txt

Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.

---

📝 Walkthrough

Walkthrough

This change adds a marker file for the stacked pull request workflow test.

Changes

Stacked workflow test

Layer / File(s)	Summary
Workflow test marker .github/stack-test/base.txt	Adds a marker file used to exercise the stacked pull request workflow.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~2 minutes

Merge Risk: ⚪ Minimal · up to 5f2f3

This adds a marker file for the stacked pull request workflow test and introduces no identified production or user-facing risk.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the addition of the stack test base marker.
Description check	✅ Passed	The description explains what changed, why the change exists, and that the file is inert. The UI section and checklist are omitted, but no UI changes apply and the core information is present.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch t3code/dummy-stack-base

---

_{Comment @coderabbitai help to get the list of available commands.}

[macroscopeapp]

Approvability

Verdict: Approved at 5f2f3db

Macroscope's review found this PR approvable — This adds only a text marker used to exercise the stacked pull request workflow. Its effect is confined to workflow testing and does not alter product behavior, defaults, deployment, or static-analysis configuration.

^{You can add or adjust custom eligibility rules. Learn more.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.5 KiB	13.6 KiB	+24 B (+0.2%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.0 KiB	7.0 KiB	+8 B (+0.1%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.5 KiB	+16 B (+0.2%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	57.0 KiB	57.0 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	8	8	0 (0.0%)	21	✅
Claude	Total thread wire	13.6 KiB	13.6 KiB	−27 B (−0.2%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.0 KiB	7.0 KiB	+4 B (+0.1%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.5 KiB	6.5 KiB	−31 B (−0.5%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.8 KiB	57.8 KiB	−44 B (−0.1%)	66.4 KiB	✅
Claude	Live turn messages	9	8	−1 (−11.1%)	21	✅

Baseline: e16b8b0 · PR result: 5f2f3db · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 113.9 KiB
• Claude decoded thread snapshot: 114.6 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[juliusmarminge]

Disposable stack-test base marker — stack merge/rebase landed in #10875. Closing as expected after the stack test.