Remove unused toInitializing() transitions from Draining and Failed

These transitions are valid in the proposal's state machine but have no
callers today — reload/recovery is deferred. Removing to avoid premature
API commitment; they can be re-added when reload is implemented.

Assisted-by: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Sam Barker <sam@quadrocket.co.uk>

Author: SamBarker

kroxylicious-runtime/src/main/java/io/kroxylicious/proxy/internal/VirtualClusterLifecycleState.java

@@ -65,13 +65,6 @@ public Stopped toStopped() {
             return new Stopped(null);
         }
 
-        /**
-         * Drain complete, cluster reinitialising with new configuration.
-         * @return the new initializing state
-         */
-        public Initializing toInitializing() {
-            return new Initializing();
-        }
     }
 
     /** Configuration was not viable. All resources have been released. */
@@ -88,14 +81,6 @@ record Failed(Throwable cause) implements VirtualClusterLifecycleState {
         public Stopped toStopped() {
             return new Stopped(cause);
         }
-
-        /**
-         * A retry is requested with corrected configuration.
-         * @return the new initializing state
-         */
-        public Initializing toInitializing() {
-            return new Initializing();
-        }
     }
 
     /** Terminal state. The cluster has been permanently removed. */