fix(cloud): reconcile resumed events by leaf identity

[tatoalo]

Problem

Resume hydration cannot safely reconcile promptless or repeated live events by content alone.

Changes

Adds leaf-scoped event ordinals and deterministic resume reconciliation.

[tatoalo]

• feat(cloud): expose steering controls for cloud sessions #3541
• fix(cloud): hydrate resumed transcripts atomically #3540
• fix(cloud): reconcile resumed events by leaf identity #3539 👈 (View in Graphite)
• feat(cloud): negotiate idempotent steer delivery #3538
• feat(cloud): add native steering to agent adapters #3537
• main

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[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 2ad530a.}

[posthog]

👋 Visual changes detected for this PR.

Review and approve in PostHog Visual Review

If these changes are unexpected, they may be caused by a flaky test or a broken snapshot on master. Don't approve — rerun the job or wait for a fix.

[stamphog]

The PR exceeds the automated review size ceiling (1160 lines), and more importantly has zero reviews on a complex behavioral change to core session hydration and event reconciliation logic. Request a team review before re-requesting auto-approval.

[trunk-io]

😎 Merged directly without going through the merge queue, as the queue was empty and the PR was up to date with the target branch - details.