Mark etcd-local-tester as deprecated so we can remove it in future.

Signed-off-by: James Blair <mail@jamesblair.net>

tools/local-tester/README.md

@@ -1,5 +1,8 @@
 # etcd local-tester
 
+> [!WARNING]
+> etcd-local-tester is now deprecated in favor of our much more comprehensive [robustness testing suite](https://github.com/etcd-io/etcd/tree/main/tests/robustness). In a future etcd release this historic tool will be removed as it is no longer maintained.
+
 The etcd local-tester runs a fault injected cluster using local processes. It sets up an etcd cluster with unreliable network bridges on its peer and client interfaces. The cluster runs with a constant stream of `Put` requests to simulate client usage. A fault injection script periodically kills cluster members and disrupts bridge connectivity.
 
 # Requirements

tools/local-tester/bridge.sh

@@ -1,5 +1,7 @@
 #!/bin/sh
 
+echo "Warning: etcd-local-tester is now deprecated in favor of our robustness testing suite and will be removed in a future release."
+
 exec tools/local-tester/bridge/bridge \
   -delay-accept    \
   -reset-listen    \

tools/local-tester/bridge/bridge.go

@@ -13,6 +13,8 @@
 // limitations under the License.
 
 // Package main is the entry point for the local tester network bridge.
+// Deprecated: etcd local tester is now deprecated. Use the etcd robustness
+// testing suite instead to validate etcd behaviour under failure conditions.
 package main
 
 import (

tools/local-tester/bridge/dispatch.go

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Deprecated: etcd local tester is now deprecated. Use the etcd robustness
+// testing suite instead to validate etcd behaviour under failure conditions.
 package main
 
 import (