Phase 3 PR 35 — IHistoryProvider gains ReadAtTimeAsync + ReadEventsAsync; GalaxyProxyDriver implements both. Extends Core.Abstractions.IHistoryProvider with two new methods that round out the OPC UA Part 11 HistoryRead surface (HistoryReadAtTime + HistoryReadEvents are the last two modes not covered by the PR 19-era ReadRawAsync + ReadProcessedAsync) and wires GalaxyProxyDriver to call the existing PR-10/PR-11 IPC contracts the Host already implements.

Interface additions use C# default interface implementations that throw NotSupportedException — existing IHistoryProvider implementations keep compiling, only drivers whose backend carries the relevant capability override. This matches the 'capabilities are optional per driver' design already used by IHistoryProvider.ReadProcessedAsync's docs (Modbus / OPC UA Client drivers never had an event historian and the default-throw path lets callers see BadHistoryOperationUnsupported naturally). New HistoricalEvent record models one historian row (EventId, SourceName, EventTimeUtc + ReceivedTimeUtc — process vs historian-persist timestamps, Message, Severity mapped to OPC UA's 1-1000 range); HistoricalEventsResult pairs the event list with a continuation-point token for future batching. Both live in Core.Abstractions so downstream (Proxy, Host, Server) reference a single domain shape — no Shared-contract leak into the driver-facing interface.
GalaxyProxyDriver.ReadAtTimeAsync maps the domain DateTime[] to Unix-ms longs, calls CallAsync on the existing MessageKind.HistoryReadAtTimeRequest, and trusts the Host's one-sample-per-requested-timestamp contract (the Host pads with bad-quality snapshots for timestamps it can't interpolate; re-aligning on the Proxy side would duplicate the Host's interpolation policy logic). ReadEventsAsync does the same for HistoryReadEventsRequest; ToHistoricalEvent translates GalaxyHistoricalEvent (MessagePack-annotated, Unix-ms) to the domain record, explicitly tagging DateTimeKind.Utc on both timestamp fields so downstream serializers (JSON, OPC UA types) don't apply an unexpected local-time offset.
Tests — HistoricalEventMappingTests (3 new Proxy.Tests unit cases): every field maps correctly from wire to domain; null SourceName and null DisplayText preserve through the mapping (system events without a source come out with null so callers can distinguish them from alarm events); both timestamps come out as DateTimeKind.Utc (regression guard against a future refactor using DateTime.FromFileTimeUtc or similar that defaults to Unspecified). Driver.Galaxy.Proxy.Tests Unit suite: 17 pass / 0 fail (14 prior + 3 new). Full solution build clean, 0 errors.
Scope exclusions — DriverNodeManager HistoryRead service-handler wiring (on the OPC UA Server side, where HistoryReadAtTime and HistoryReadEvents service requests land) and the full-loop integration test (OPC UA client → server → IPC → Host → HistorianDataSource → back) are deferred to a focused follow-up PR. The capability surface is the load-bearing change; wiring the service handlers is mechanical in comparison and worth its own PR for reviewability. docs/v2/lmx-followups.md #1 updated with the split.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/v2/lmx-followups.md

@@ -9,19 +9,18 @@ rough priority order.
 
 ## 1. Proxy-side `IHistoryProvider` for `ReadAtTime` / `ReadEvents`
 
-**Status**: Host-side IPC shipped (PR 10 + PR 11). Proxy consumer not written.
+**Status**: Capability surface complete (PR 35). OPC UA HistoryRead service-handler
+wiring in `DriverNodeManager` remains as the next step; integration-test still
+pending.
 
-PR 10 added `HistoryReadAtTimeRequest/Response` on the IPC wire and
-`MxAccessGalaxyBackend.HistoryReadAtTimeAsync` delegates to
-`HistorianDataSource.ReadAtTimeAsync`. PR 11 did the same for events
-(`HistoryReadEventsRequest/Response` + `GalaxyHistoricalEvent`). The Proxy
-side (`GalaxyProxyDriver`) doesn't call those yet — `Core.Abstractions.IHistoryProvider`
-only exposes `ReadRawAsync` + `ReadProcessedAsync`.
+PR 35 extended `IHistoryProvider` with `ReadAtTimeAsync` + `ReadEventsAsync`
+(default throwing implementations so existing impls keep compiling), added the
+`HistoricalEvent` + `HistoricalEventsResult` records to
+`Core.Abstractions`, and implemented both methods in `GalaxyProxyDriver` on top
+of the PR 10 / PR 11 IPC messages. Wire-to-domain mapping (`ToHistoricalEvent`)
+is unit-tested for field fidelity, null-preservation, and `DateTimeKind.Utc`.
 
-**To do**:
-- Extend `IHistoryProvider` with `ReadAtTimeAsync(string, DateTime[], …)` and
-  `ReadEventsAsync(string?, DateTime, DateTime, int, …)`.
-- `GalaxyProxyDriver` calls the new IPC message kinds.
+**Remaining**:
 - `DriverNodeManager` wires the new capability methods onto `HistoryRead`
   `AtTime` + `Events` service handlers.
 - Integration test: OPC UA client calls `HistoryReadAtTime` / `HistoryReadEvents`,