The chat surface now relies on the current-turn changes card for file rollback, so the older per-message hover rewind affordance was removed to avoid two competing rollback models.
Constraint: Current-turn undo still depends on the existing checkpoint rewind API.
Rejected: Keep both rewind entry points | duplicate rollback affordances make the product harder to explain and test.
Confidence: high
Scope-risk: moderate
Directive: Prefer adding rollback behavior through the current-turn change card instead of restoring per-message hover rewind.
Tested: bun test src/server/__tests__/sessions.test.ts
Tested: cd desktop && bun run test
Tested: cd desktop && bun run lint
Tested: cd desktop && bun run build
Not-tested: Browser E2E scripts were updated but not executed in this commit.
Desktop rewind previously used the visible user-message index as the primary selector. That can drift from the persisted active chain when hidden or non-rendered user messages exist, so the API now prefers a stable user message id and checks the selected prompt text before mutating transcript or files.
Constraint: Desktop UI can hide transcript entries that still exist in the persisted session chain
Rejected: Keep index-only rewind | can target an earlier user message after UI/server chain drift
Confidence: high
Scope-risk: moderate
Directive: Do not remove targetUserMessageId or expectedContent guards without reproducing shifted visible-index sessions
Tested: bun test src/server/__tests__/sessions.test.ts --timeout 20000
Tested: cd desktop && bun run test MessageList.test.tsx chatStore.test.ts -- --run
Tested: desktop/scripts/e2e-rewind-agent-browser.sh
Tested: desktop/scripts/e2e-rewind-complex-agent-browser.sh
Not-tested: Full desktop Vitest suite still has unrelated locale-sensitive failures
