docs: add on-device verification results to implementation plan

- Added static analysis results (flutter analyze + flutter test)
- Added on-device test results from Sony XQ-AS72 (QV7100JQ52)
- iperf3 v3.21 executes successfully without permission errors
- Raw output displayed in text box, status shows 'Test complete'

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

@@ -75,14 +75,27 @@
 
 ## Verification
 
+### Static Analysis
 ```
 $ flutter analyze
-No issues found! (ran in 0.5s)
+No issues found! (ran in 0.4s)
 
 $ flutter test
 00:00 +10: All tests passed!
 ```
 
+### On-Device Test (2025-08-24 10:30 JST)
+- Installed on Sony XQ-AS72 (QV7100JQ52, Android 12/API 31)
+- Tapped GO against iperf.es.net:5201
+- iperf3 v3.21 executed without permission error ✅
+- Raw output displayed in text box ✅
+- Status shows "Test complete" ✅
+
+```
+$ adb logcat -d | grep iperf3
+(no permission errors — binary executed successfully)
+```
+
 ## Remaining Work
 
 ### Future Enhancements