[cherry-pick] Hide session chat pills in subagent chats - #334827

PR classified as community.

⚠️ This PR is labelled cherry-pick-artifact but did not qualify for the reduced cherry-pick approval requirement: the patch differs from source PR #334510 (git patch-id or whitespace-sensitive mismatch) — not an identical cherry-pick. The standard requirement applies.

⚠️ Head commit is NOT signed by a trusted team member, so the full 3-approval requirement applies. (Head commit 84ecaa1 is signed by GitHub, not by a trusted team member. GitHub adds its own "Verified" signature to commits it creates on your behalf — e.g. edits made in the github.com web editor, suggestions applied from a review, or commits made via Codespaces or the GitHub API. That signature only proves GitHub made the commit, not that a trusted team member authored it, so it does not earn the signing credit. To get the credit, create the commit locally, and sign it with a trusted key.)

Tip: to earn the credit (−1 approval), the head commit must be signed by you with one of your own keys listed in security/trusted-signing-keys.csv. A "Verified" badge that GitHub adds to commits it creates on your behalf — web-editor edits, applied suggestions, Codespaces, API commits — does not count.

⚠️ Collaborator approvals: 0/3.

Needs 3 more collaborator approvals to merge.

✅ No newly added runnable binary files.

✅ No protected engineering system files changed.

Automation rules

⚠️ cherry-pick automation rules reported 1 finding.

• The cherry-pick diff does not match the merged source PR: the patch differs from source PR #334510 (git patch-id or whitespace-sensitive mismatch) — not an identical cherry-pick.

❌ The automation rules did not pass, so this check fails.