fix: expose web-probe diagnostic previews (#623)

Co-authored-by: Codex <codex@noreply.local>

scripts/src/hwlab-node-impl.ts

@@ -7075,7 +7075,7 @@ function runNodeWebProbeObserveStatus(options: NodeWebProbeObserveOptions, spec:
     observer: withWebObserveShortcuts(status, observerId),
     index,
     next: observerId === null ? null : webObserveNextCommands(observerId),
-    result: compactCommandResult(result),
+    result: compactCommandResultWithStdoutTail(result),
     valuesRedacted: true,
   });
 }
@@ -7308,7 +7308,7 @@ function runNodeWebProbeObserveCollect(options: NodeWebProbeObserveOptions, spec
     lane: options.lane,
     workspace: spec.workspace,
     collect,
-    result: compactCommandResult(result),
+    result: compactCommandResultWithStdoutTail(result),
     valuesRedacted: true,
   };
 }
@@ -11268,12 +11268,18 @@ function compactCommandResult(result: CommandResult): Record<string, unknown> {
     command: compactCommand(result.command),
     exitCode: result.exitCode,
     stdoutBytes: result.stdout.length,
-    stdoutTail: result.stdout.trim().slice(-2000),
+    stdoutTail: result.exitCode === 0 && !result.timedOut ? "" : result.stdout.trim().slice(-2000),
     stderr: result.exitCode === 0 ? "" : result.stderr.trim().slice(0, 2000),
     timedOut: result.timedOut,
   };
 }
 
+function compactCommandResultWithStdoutTail(result: CommandResult): Record<string, unknown> {
+  const compact = compactCommandResult(result);
+  compact.stdoutTail = result.stdout.trim().slice(-2000);
+  return compact;
+}
+
 function compactCommandResultRedacted(result: CommandResult, secrets: string[]): Record<string, unknown> {
   const compact = compactCommandResult(result);
   if (typeof compact.stderr === "string" && compact.stderr.length > 0) {