docs(handoff): refresh event-row item — captured + v8 connection-type gate

Item 1 is no longer capture-gated (the capture is done, merged 8ad160b). Update it
to: the capture-event run read 50 events from the stock client; the v6 request is
shipped; the remaining gate is the native v8 Event-type OpenConnection (a
ConnectionType field the SDK's v6 Open2 format lacks), a scoped RE+impl follow-on.
Points at docs/reverse-engineering/grpc-event-query-capture.md. Also corrected the
"to move any item" summary so item 1 no longer reads as needing a fresh capture.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC

docs/reverse-engineering/handoff.md

@@ -38,18 +38,26 @@ reuses the proven 2020 WCF byte serializers/parsers unchanged inside protobuf
 
 **Everything still open is gated — none is a pure-code task:**
 
-1. **gRPC event ROW retrieval** (`ReadEventsAsync` #2) — chain + StartEventQuery
-   work; `GetNextEventQueryResultBuffer` long-polls and returns zero rows.
-   **Re-characterized 2026-06-22: this is capture-gated, NOT server-gated.** The
-   earlier "needs an event-bearing 2023 R2 server" assumption is **disproven** —
-   the live 2023 R2 server *is* event-bearing (SQL ground truth via the INSQL
-   linked server: `Runtime.dbo.Events` = 19,356 rows in the last 30 days /
-   90,944 in 365 days), yet the **empty-filter** gRPC event query still yields
-   zero rows over that exact 30-day window and long-polls to the deadline. So
-   the gap is in the empty-filter request shape (filter / namespace / event-tag
-   registration), not data availability. Needs a **fresh native gRPC
-   event-query capture** to see what the stock 2023 R2 client sends. Bounded
-   ≤30s, throws on no-row.
+1. **gRPC event ROW retrieval** (`ReadEventsAsync` #2) — **CAPTURED + DIAGNOSED
+   2026-06-22 (merged `8ad160b`); remaining gate is now a scoped RE+impl effort,
+   not a capture.** The `capture-event` harness scenario drove the stock 2023 R2
+   client over an Event-type gRPC connection and captured it reading **50 events**
+   (the live server is event-bearing — SQL ground truth via the INSQL linked
+   server: `Runtime.dbo.Events` = 19,356 rows/30d, 90,944/365d). Two gaps vs the
+   SDK: **(a)** the working `StartEventQuery` request is **version 6** (byte 0 =
+   `06` + a 5-byte trailing pad), the SDK sent v5 — **SHIPPED**
+   (`HistorianEventQueryProtocol` `version` param, default 5 = WCF; the gRPC
+   orchestrator passes 6; golden-tested). **(b) the real gate:** rows flow only on
+   an **Event-type connection**. The native `OpenConnection.openParameters` is
+   format **v8** with a `ConnectionType` byte (Event `01` / Process `02`) right
+   after `ClientType`; the SDK's **v6** Open2 buffer has no such field (it writes
+   `ClientType` then `ConnectionMode` back-to-back), so the read-capable v6
+   connection cannot be marked as Event. `ConnectionMode` is not the lever (2020
+   WCF events work at `0x402`). Making event rows flow needs the SDK to emit the
+   native v8 `OpenConnection` with `ConnectionType=Event` (and likely the
+   `ExchangeKey` cert auth path) — a substantial follow-on. Full evidence +
+   byte-level diagnosis: `docs/reverse-engineering/grpc-event-query-capture.md`.
+   Gated test still pins the no-row throw; bounded ≤30s.
 2. **R4.3 active-SF magnitude** — needs an **SF-active server** (D2 storage-engine
    console handle).
 3. **SendEvent over gRPC** — **capture-gated**: no distinct RPC, framing uncaptured.
@@ -67,10 +75,11 @@ reuses the proven 2020 WCF byte serializers/parsers unchanged inside protobuf
 8. **Deferred-by-design** items (`write-commands` D1–D3, non-analog tag create,
    etc.) — bounded out until an explicit customer/user demand signal.
 
-To move any remaining item you need a **fresh native capture** (gRPC event-query
-empty-filter framing — item 1; SendEvent gRPC framing — item 3), a **different
-server** (SF-active for item 2), or a **demand signal** to unlock a deferred
-item. Live-server gRPC probe recipe: set
+To move any remaining item you need a **scoped RE+impl effort** (the v8
+Event-type `OpenConnection` — item 1, already captured + diagnosed), a **fresh
+native capture** (SendEvent gRPC framing — item 3), a **different server**
+(SF-active for item 2), or a **demand signal** to unlock a deferred item.
+Live-server gRPC probe recipe: set
 `HISTORIAN_GRPC_HOST`/`_PORT 32565`/`_TLS true`/`_DNSID` + domain creds (strip
 quotes — `reference_wonder_sql_vd03_credentials`) and run the gated
 `HistorianGrpcIntegrationTests`.