fix(#1962): pin harness SyslogIdentifier so otel ExecStart wrapper doesn't rename the log unit

nix/templates/harness-base.nix

@@ -1775,6 +1775,13 @@ in
         // otelEnv;
         serviceConfig = {
           ExecStart = if otel.enable then "${otelExecStart}" else "${pkgs.hyperhive}/bin/${binary} serve";
+          # Pin the journal identity to the binary name. Without this,
+          # systemd derives SyslogIdentifier from the ExecStart basename —
+          # which under OTEL is the wrapper script's store path
+          # (`<hash>-hive-serve-otel`), so every agent's harness logs showed
+          # that opaque name instead of `hive`. Set explicitly so the
+          # identity is stable across the otel / non-otel ExecStart branches.
+          SyslogIdentifier = binary;
           Restart = "on-failure";
           RestartSec = 2;
           # Per-service runtime dir owned by `User=` below; the harness