## Summary
- retire Virtua prepend reconciliation on every ordinary reader wheel
event, including events suppressed from its separate wheel-timing
heuristic
- keep Ctrl+wheel browser zoom excluded from reader ownership
- arm the Ctrl+wheel prepend probe before pagination begins so it cannot
miss the commit
- preserve ESM/CJS patch parity and update the patch lock hash
## Why main was red
PR #2855 added the reader-wheel retirement action after Virtua's
existing suppression guard. Once the first event set that guard, later
events in the same wheel burst returned before retiring prepend mode. A
late ResizeObserver correction could then pull the viewport backward by
20–40px. The same test had failed twice on #2855 but passed its final
retry, so the PR job appeared green; the merge commit lost all three
retries.
The separate Ctrl+wheel failure was a test race: its MutationObserver
was registered after the request had already been triggered and could
miss the prepend commit.
## Validation
- desktop full unit suite: 3,515 passed
- pre-push desktop check: passed
- `git diff --check`: passed
- CI is the E2E verification; no local E2E was run
Fixes the main-branch failure in CI run 30180099007.
Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Carl <c7ebe626f000404285d3686e1dc74cc07cc60a9754a150041ba132e14bd3e2ec@buzz.block.builderlab.xyz>
## Summary
- make Virtua the sole prepend geometry/correction owner by accumulating
active prepend ResizeObserver corrections from the live DOM offset
- retire prepend reconciliation on ordinary reader wheel input, while
preserving it for Ctrl+wheel browser zoom
- remove Buzz's competing three-second semantic-anchor watcher and
corrective `scrollBy` loop
- keep ESM/CJS Virtua patch behavior equivalent and update the patch
lock hash
## Why
Buzz admitted prepended rows using seeded estimates, then Virtua
received multiple measurement corrections for the same transaction. Each
correction was based on the same stale model offset, so a later write
replaced an earlier correction instead of accumulating it. In the
reproduced first page, that resurrected 452px of anchor drift; the
app-level watcher merely corrected the lost virtualizer write afterward.
This fixes the correction inside Virtua and deletes the competing app
writer, following the single-owner geometry invariant used by Berd
rather than copying its spacer implementation.
## Validation
- watcher-off desktop virtualization matrix: 11/11 passed, including 15
cascading prepends, continued wheel input, detached rich-row growth,
channel switching, bottom follow, and buffered live arrivals
- focused cascading prepend/Ctrl+wheel regression passed
- desktop typecheck passed
- desktop unit suite passed: 3,495 tests
- Biome passed on changed desktop files
- `git diff --check` clean
## Manual behavior
Load older history repeatedly while scrolling upward, then wheel
downward during/after a prepend. The visible anchor should stay within
the existing 5px contract during reconciliation, and deliberate reader
movement should not be pulled back. Ctrl+wheel during the prepend commit
must not cancel reconciliation.
---------
Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Carl <c7ebe626f000404285d3686e1dc74cc07cc60a9754a150041ba132e14bd3e2ec@sprout-oss.stage.blox.sqprod.co>
Co-authored-by: Carl <c7ebe626f000404285d3686e1dc74cc07cc60a9754a150041ba132e14bd3e2ec@buzz.block.builderlab.xyz>
