Make the e2e write phase work live across all five clients

Running the matrix against a live gateway surfaced several issues:

- The write phase is now opt-in (-VerifyWrite, was -SkipWrite). It runs
  right after register so only a small event backlog precedes the write,
  and asserts the reliable OnWriteComplete signal (the written value is
  not echoed back by a provider-driven attribute like TestChangingInt, so
  the value compare is best-effort).
- Java was launched as bare "gradle", which .NET's Process.Start cannot
  exec (it is gradle.bat) — resolve the launcher and run it via cmd.exe.
- The Java client's MxEventStream queue capacity was 16, which overflows
  on any active session's backlog-replay burst; raised to 1024.
- The Rust stream-events CLI now renders the event family as the proto
  enum name, matching the protobuf-JSON the other four clients emit.

Update docs/GatewayTesting.md for the reworked write phase.

Verified live: the full five-client matrix passes with -VerifyWrite.

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

clients/java/mxgateway-client/src/main/java/com/dohertylan/mxgateway/client/MxGatewayClient.java

@@ -260,7 +260,12 @@ public final class MxGatewayClient implements AutoCloseable {
      * @return an iterator-style stream of events
      */
     public MxEventStream streamEvents(StreamEventsRequest request) {
-        MxEventStream stream = new MxEventStream(16);
+        // The buffer must absorb the gateway's session-backlog replay burst,
+        // which arrives far faster than the iterator drains it. A small queue
+        // overflows on any moderately active session; 1024 covers a realistic
+        // backlog while still bounding memory and preserving overflow
+        // detection for a genuinely unbounded stream.
+        MxEventStream stream = new MxEventStream(1024);
         MxGatewayChannels.withStreamDeadline(rawAsyncStub(), options).streamEvents(request, stream.observer());
         return stream;
     }

clients/rust/crates/mxgw-cli/src/main.rs

@@ -17,7 +17,7 @@ use clap::{Args, Parser, Subcommand, ValueEnum};
 use futures_util::StreamExt;
 use mxgateway_client::generated::galaxy_repository::v1::DeployEvent;
 use mxgateway_client::generated::mxaccess_gateway::v1::{
-    CloseSessionRequest, MxCommand, MxCommandKind, MxCommandRequest, MxEvent,
+    CloseSessionRequest, MxCommand, MxCommandKind, MxCommandRequest, MxEvent, MxEventFamily,
     MxValue as ProtoMxValue, OpenSessionRequest, PingCommand, StreamEventsRequest,
 };
 use mxgateway_client::{
@@ -842,8 +842,13 @@ fn print_deploy_event(event: &DeployEvent, use_json: bool) {
 /// matrix can extract and compare event values uniformly across all five
 /// client CLIs.
 fn event_to_json(event: &MxEvent) -> Value {
+    // Render the family as the proto enum name (e.g. MX_EVENT_FAMILY_ON_WRITE_COMPLETE)
+    // so it matches the protobuf-JSON the .NET/Go/Java/Python CLIs emit.
+    let family = MxEventFamily::try_from(event.family)
+        .map(|family| family.as_str_name().to_owned())
+        .unwrap_or_else(|_| event.family.to_string());
     json!({
-        "family": event.family,
+        "family": family,
         "sessionId": event.session_id,
         "serverHandle": event.server_handle,
         "itemHandle": event.item_handle,