Fix live-tail Load New Events not rendering the new row until reload

[jschick04]

Problem

Open a log, let the watcher buffer a new event (status bar shows "New Events: 1", continuously-update OFF), then click View > Load New Events. The count clears but the new row does not appear until a full log reload.

Root cause

LogReloadEffects.ProcessNewEventBuffer (and FilteringEffects.HandleAddEvent on the continuously-update path) dispatched IngestRawEventsAction and then read _rawEventStore.Value in the same effect to build the display view. Fluxor 6.10.0 queues nested dispatches, so that read saw the pre-ingest store: the rebuilt view omitted the new event while the buffer count was cleared regardless. A full reload worked only because it uses reducer-before-effect ordering.

Fix

• New effect-only RebuildDisplayViewsAction(NewEventsByLog, ClearNewEventBuffer).
• Both producers now dispatch IngestRawEventsAction then RebuildDisplayViewsAction. Fluxor drains the ingest reducer before the new HandleRebuildDisplayViews effect runs, so the rebuild reads the post-ingest store.
• The continuation owns the new-event buffer clear and fires it only after a successful rebuild (preserved on throw; a legitimately empty / all-filtered rebuild still clears).
• Also removes the one-event lag on the continuously-update live-tail path.

Tests

• Replaced three inline-ingest test mocks that masked the bug with a queue-faithful drain harness (CaptureDispatchQueue + DrainDispatchQueueAsync) that applies the ingest reducer only during drain, so a same-effect pre-ingest read fails the assertions.
• Added regression (row appears after load), two-event interleaving (both concurrent events survive), and clear-on-throw (buffer preserved on rebuild failure) coverage.
• Build clean; EventLogExpert.Runtime.Tests 2020/2020 green.

Notes

• Live-tail single-append now routes through AppendTableEventsBatchAction, which clears the log's PerLogListVersion entry. Verified display-inert (no production consumer).

[Copilot]

Pull request overview

This PR fixes a Fluxor nested-dispatch ordering issue where “Load New Events” (and continuously-update live tail) would clear the new-event counter but not render the newly ingested rows until a full reload, by separating “ingest raw events” from “rebuild display views” into distinct queued actions/effects.

Changes:

• Introduces RebuildDisplayViewsAction and a new HandleRebuildDisplayViews effect that rebuilds views after raw ingest reducers have applied.
• Updates the live-tail and buffered “Load New Events” producers to dispatch IngestRawEventsAction followed by RebuildDisplayViewsAction, with buffer clearing moved to the continuation.
• Refactors/adds tests to simulate Fluxor’s queued nested-dispatch behavior and adds regressions for ordering, interleaving, and clear-on-throw behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
tests/Unit/EventLogExpert.Runtime.Tests/EventLog/EffectsTests.cs	Updates/extends tests to be queue-faithful and adds regressions for the stale-read/live-tail lag scenario.
src/EventLogExpert.Runtime/EventLog/RebuildDisplayViewsAction.cs	Adds a new internal action to trigger post-ingest display rebuilds.
src/EventLogExpert.Runtime/EventLog/LogReloadEffects.cs	Adds HandleRebuildDisplayViews effect and routes buffered “Load New Events” through the new continuation.
src/EventLogExpert.Runtime/EventLog/FilteringEffects.cs	Updates continuously-update live-tail path to queue the rebuild action after ingest (no same-effect stale reads).

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