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/rust/src/session.rs

@@ -533,7 +533,10 @@ impl Session {
     /// returning the most recent cached `OnDataChange` value when the tag is
     /// already advised (`was_cached = true`), or by taking a full AddItem +
     /// Advise + wait + UnAdvise + RemoveItem snapshot lifecycle otherwise.
-    /// `timeout_ms == 0` lets the worker pick its default (1000 ms).
+    /// `timeout_ms` is one shared 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. `timeout_ms == 0` lets the worker
+    /// pick its default (1000 ms).
     /// Per-tag failures appear as `BulkReadResult` entries with
     /// `was_successful = false`; the call never errors on per-tag failure.
     ///