fix: suppress routine ssh timing noise

scripts/src/help.ts

@@ -178,7 +178,7 @@ export function sshHelp(): unknown {
       "Do not put operation names in any colon route segment, including nested k3s namespace/workload/container segments.",
       "Do not use post-provider shorthand such as `ssh G14 k3s ...`; write `ssh G14:k3s ...` so location and operation stay separated.",
       "If an ssh-like remote command fails with timeout/kex/exit-255 friction, stderr includes one low-noise UNIDESK_SSH_HINT JSON line with the argv retry command.",
-      "Every ssh/tran runtime writes one UNIDESK_SSH_TIMING JSON line to stderr with elapsedMs/elapsedSeconds; operations over 10s are marked level=warning and should be checked for provider latency, remote command cost, helper bootstrap, or tran/apply-patch optimization before repeating high-frequency work.",
+      "Only slow ssh/tran runtime writes UNIDESK_SSH_TIMING JSON to stderr; operations over 10s are marked level=warning and should be checked for provider latency, remote command cost, helper bootstrap, or tran/apply-patch optimization before repeating high-frequency work. Routine short calls do not emit timing noise.",
       "The local tran wrapper serializes non-interactive calls per provider/plane before opening provider SSH sessions, so parallel Codex file reads do not stampede the provider session allocator; set UNIDESK_TRAN_SESSION_LOCK=0 only for explicit diagnostics.",
       "Use -- before a remote command that intentionally starts with a dash.",
     ],

scripts/src/remote.ts

@@ -968,12 +968,13 @@ async function runRemoteSshWebSocket(
       restore();
       const hint = sshFailureHint(invocation.providerId, parsed, code, "");
       if (hint !== null) process.stderr.write(formatSshFailureHint(hint));
-      process.stderr.write(formatSshRuntimeTimingHint(sshRuntimeTimingHint({
+      const timingHint = formatSshRuntimeTimingHint(sshRuntimeTimingHint({
         invocation,
         transport: "frontend-websocket",
         exitCode: code,
         startedAtMs,
-      })));
+      }));
+      if (timingHint) process.stderr.write(timingHint);
       resolve(code);
     };
     const onStdinData = (chunk: Buffer): void => {

scripts/src/ssh.ts

@@ -1626,6 +1626,7 @@ export function sshRuntimeTimingHint(options: {
 }
 
 export function formatSshRuntimeTimingHint(hint: SshRuntimeTimingHint): string {
+  if (!hint.slow) return "";
   return `UNIDESK_SSH_TIMING ${JSON.stringify(hint)}\n`;
 }
 
@@ -1836,12 +1837,13 @@ export async function runSsh(config: UniDeskConfig, providerId: string, args: st
       restore();
       const hint = sshFailureHint(invocation.providerId, parsed, exitCode, stderrTail);
       if (hint !== null) process.stderr.write(formatSshFailureHint(hint));
-      process.stderr.write(formatSshRuntimeTimingHint(sshRuntimeTimingHint({
+      const timingHint = formatSshRuntimeTimingHint(sshRuntimeTimingHint({
         invocation,
         transport: "backend-core-broker",
         exitCode,
         startedAtMs,
-      })));
+      }));
+      if (timingHint) process.stderr.write(timingHint);
       resolve(exitCode);
     };
     child.on("error", (error) => {