docs(clients): ReadBulk timeout is one shared deadline for the command, not per tag

Stream E made the worker wait once for all uncached tags. Fix the Go, Python, Rust, Java
and .NET library docs and CLI help text, the proto comment (default is the worker's
1000 ms), and the worker design doc. Regenerated Contracts Generated/ and the Java
generated protos; both diffs are comment-only.

clients/dotnet/ZB.MOM.WW.MxGateway.Client/MxGatewaySession.cs

@@ -641,7 +641,7 @@ public sealed class MxGatewaySession : IAsyncDisposable
     /// </summary>
     /// <param name="serverHandle">The ServerHandle from register.</param>
     /// <param name="tagAddresses">Tag addresses to read (one per result).</param>
-    /// <param name="timeout">Per-call timeout for the snapshot lifecycle path; <see cref="TimeSpan.Zero"/> uses the gateway default.</param>
+    /// <param name="timeout">One shared snapshot deadline for the whole command, not a per-tag budget: the worker advises every uncached tag, waits once for all of them, then tears them down. <see cref="TimeSpan.Zero"/> uses the worker default (1000 ms).</param>
     /// <param name="cancellationToken">Cancellation token.</param>
     /// <returns>One <see cref="BulkReadResult"/> per requested tag, in request order.</returns>
     public async Task<IReadOnlyList<BulkReadResult>> ReadBulkAsync(