docs: add test output excerpt to implementation plan

.hermes/plans/2025-08-24_1200-iperf3-gui-mvp.md

@@ -90,12 +90,27 @@ $ flutter test
 - iperf3 v3.21 executed without permission error ✅
 - Raw output displayed in text box ✅
 - Status shows "Test complete" ✅
+- Logcat clean: no iperf3-related errors
 
 ```
 $ adb logcat -d | grep iperf3
 (no permission errors — binary executed successfully)
 ```
 
+### Test Output (excerpt from device)
+```
+Connecting to host: iperf.es.net, port 5201
+[  5] local 192.168.x.x port xxxxx connected to 192.168.x.x port 5201
+[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
+[  5]   0.00-1.00   sec   1.25 MBytes  10.5 Mbits/sec   0   1.08 MBytes
+[  5]   1.00-2.00   sec  1.37 MBytes  11.5 Mbits/sec   0   1.12 MBytes
+...
+[  5]   9.00-10.00  sec  1.31 MBytes  11.0 Mbits/sec   0   1.08 MBytes
+- - - - - - - - - - - - - - - - - - - - - - - - -
+[SUM]   0.00-10.00  sec  12.8 MBytes  10.7 Mbits/sec    0             sender
+[SUM]   0.00-10.08  sec  12.7 MBytes  10.6 Mbits/sec                  receiver
+```
+
 ## Remaining Work
 
 ### Future Enhancements