feat(desktop): name the cohorts a cohort's criteria reference

[puemos]

Problem

On the desktop app's cohort page, membership criteria that reference another cohort show its numeric id, for example "Is in cohort 42". A person cannot tell which cohort that is without opening PostHog.

Changes

• Membership criteria now name the referenced cohort: "Is in cohort Power users".
• The cohort page fetches each referenced cohort, capped at ten. A failed lookup keeps the id in place, so the criteria still render.
• Mechanical: cohortCriteriaSection and shapeCohortPreview take a name map, and a new referencedCohortIds helper walks the criteria.

Before, the same criteria read "Is in cohort 42 and ..." and "Is not in cohort 57 and ...".

How did you test this code?

• The existing negated-criteria test now uses cohort ids with a name map and one unresolved id. It catches a regression where a referenced cohort renders as its id, or an unresolved id renders as empty.
• The screenshot above comes from a new Storybook story with invented fixture data.
• Not run: the app against a live backend.

Automatic notifications

• Publish to changelog?

Docs update

None.

🤖 Agent context

Built in a PostHog Desktop task as the top layer of a stack on #93987. Kept to name resolution; the cohort criteria were already prose. Skills invoked: stacking-prs, writing-tests, writing-pr-descriptions.

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Created with PostHog Desktop

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 29484df.}

[github-actions]

🤖 CI report

✅ Trunk lane — non-backend lane

This PR is assigned to the non-backend lane. It does not run backend Python tests and may merge in parallel with PRs in other lanes.

[puemos]

/trunk merge

[trunk-io]

😎 Stack merged successfully - details.

[deployment-status-posthog]

Deploy status

Environment	Status	Deployed At	Workflow
dev	✅ Deployed	2026-09-07 07:32 UTC	Run
prod-us	✅ Deployed	2026-09-07 07:43 UTC	Run
prod-eu	✅ Deployed	2026-09-07 07:47 UTC	Run