Add shadow reviewer workflow

[allspain]

Motivation

Add a GitHub Actions workflow for shadow code review powered by the rum-ai-toolkit shadow reviewer.

Changes

• Added .github/workflows/shadow-review.yml workflow that:
  • Syncs the shadow fork on merges to main
  • Mirrors non-draft, non-bot PRs to the shadow fork for review

Test instructions

Workflow will trigger on PRs — verify it runs correctly on a test PR.

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.
• Updated documentation and/or relevant AGENTS.md file

🤖 Generated with Claude Code

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	178.50 KiB	178.50 KiB	0 B	0.00%	✅
Rum Profiler	6.16 KiB	6.16 KiB	0 B	0.00%	✅
Rum Recorder	26.97 KiB	26.97 KiB	0 B	0.00%	✅
Logs	57.00 KiB	57.00 KiB	0 B	0.00%	✅
Rum Slim	134.32 KiB	134.32 KiB	0 B	0.00%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base CPU Time (ms)	Local CPU Time (ms)	𝚫%
RUM - add global context	0.0048	0.0056	+16.67%
RUM - add action	0.0146	0.0155	+6.16%
RUM - add error	0.014	0.018	+28.57%
RUM - add timing	0.003	0.0032	+6.67%
RUM - start view	0.0148	0.0184	+24.32%
RUM - start/stop session replay recording	0.0009	0.0007	-22.22%
Logs - log message	0.0161	0.0147	-8.70%

🧠 Memory Performance

Action Name	Base Memory Consumption	Local Memory Consumption	𝚫
RUM - add global context	26.00 KiB	27.50 KiB	+1.49 KiB
RUM - add action	92.97 KiB	99.08 KiB	+6.12 KiB
RUM - add timing	26.37 KiB	25.52 KiB	-866 B
RUM - add error	97.51 KiB	97.85 KiB	+347 B
RUM - start/stop session replay recording	26.79 KiB	25.44 KiB	-1.35 KiB
RUM - start view	484.79 KiB	484.91 KiB	+127 B
Logs - log message	100.18 KiB	99.98 KiB	-209 B

🔗 RealWorld

[datadog-prod-us1-3]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 77.31% (+0.00%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 506f9a8 | Docs | Datadog PR Page | Was this helpful? React with 👍/👎 or give us feedback!}

[allspain]

I have read the CLA Document and I hereby sign the CLA

[ncreated]

I have read the CLA Document and I hereby sign the CLA

[0xnm]

I think it is better to use dd-octo-sts for the GH token management

[0xnm]

@codex review

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 506f9a869d

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Skip job when shadow token is unavailable on fork PRs

This job runs for all non-draft, non-bot pull_request events, but it assumes secrets.SHADOW_FORK_TOKEN is present and immediately uses it for shadow-fork access. For forked PRs (and Dependabot-style fork-restricted runs), repository secrets are not provided, so the pre-flight check fails and the workflow reports a hard failure for external contributors. Add a guard in if: (for example, same-repo PRs only) or explicitly skip when the token is missing.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Fetch enough history before calling merge-base

Both refs are fetched with a fixed shallow depth of 50 and then used to compute git merge-base. When a PR branch diverged more than 50 commits ago, the common ancestor is outside the fetched history, so git merge-base fails and the mirror job aborts for long-lived branches. This should deepen/fetch full history (or retry with increasing depth) before deriving MERGE_BASE.

Useful? React with 👍 / 👎.

[allspain]

Going to merge and address the feedback in a new PR

[BeltranBulbarellaDD]

@allspain @0xnm @ncreated Do you think we could not show the:
"allspain mentioned this pull request ..." on every CI run?
E.g:

Happy to work on it, just want to know what you think about it.