fix(cli): usage-error JSON envelope emits without logger output

Logger backends write to stdout on hosts without gum, corrupting the
parseable envelope (caught by CI, invisible on dev machines). The
envelope already carries the message.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: roodboi

src/cli/run.ts

@@ -122,10 +122,11 @@ async function handleRunCliError(opts: {
   const { error, jsonRequested } = opts;
   if (error instanceof CliUsageError) {
     if (jsonRequested) {
+      // Envelope only: the message is inside it, and logger backends may
+      // write to stdout on some hosts, corrupting the parseable output.
       emitCliResult({
         result: errorResult({ code: "E_USAGE", message: error.message }),
       });
-      logger.error({ message: error.message });
       return 1;
     }
     logger.error({ message: error.message });