[krotname]

Problem

When the gateway emits the final answer as message.interim and then sends message.complete with response_previewed: true, the chat displays the same answer twice. For example, a 3+4 request ends with two identical 7 bubbles.

Changes

• Settle previewed/transformed completions onto the sealed interim message from the current user turn. Reused completions require an exact text match.
• Respect explicit message.start boundaries, keeping separate messages and repeated user turns distinct.
• Preserve late reasoning updates, including append/replace semantics and the latest verbose/collapsed state.
• Add widget regressions covering these event sequences.

Validation

• All 20 tests in test/chat_history_scroll_test.dart passed.
• Static analysis of the changed files passed.
• Full analysis and test CI passed for the exact head commit: https://github.com/krotname/hermes-android/actions/runs/39232710402

[rusty4444]

Hermes review: two blocking reconciliation bugs. At lib/core/screens/chat_screen.dart:3299-3332, a previewed completion is reconciled with the newest interim without checking its text. With interims A then B and completion A, B is overwritten and A appears twice. Also, response_transformed means an output hook changed the final answer; a distinct transformed final can replace and lose interim commentary. The added tests use message.start between replies, but the gateway emits that at turn start, so they miss the no-intervening-delta case. Please match the actual previewed interim and preserve distinct commentary; add regressions for both. CI passed for this head, but do not merge until fixed.

[rusty4444]

Thanks @krotname for the contribution. I added a maintainer follow-up commit on your PR head (968d1cd) to settle only exact raw-text preview matches, preserve distinct transformed commentary, and cover the no-intervening-start and rendered-text cases. This keeps your original commits and authorship intact. Local full analysis and all 1,337 tests passed; current-head PR CI also passed.