Document engineering learnings and refresh handoff guidance

docs/DEVICE_TESTING.md

@@ -6,8 +6,15 @@ iPhone on the LAN** (`https://192.168.86.2:9178`) because mic input, WebRTC capt
 and audio session behavior don't work in this simulator environment (CoreAudio `-4010`,
 0 input channels).
 
-Setup: build with Xcode for a physical device (or `xcodebuild ... -destination`), install,
-ensure the server cert pin is current (see README — re-export after any server restart).
+Setup: recheck device availability and signing, then build/install with Xcode or
+the installed XcodeBuildMCP skill workflow. The phone was paired and the Nearlight
+build launched successfully on September 12; that does not prove today's availability
+or a still-valid provisioning profile. Verify the server certificate pin after an
+actual certificate rotation, not automatically after every container restart.
+
+For each check, record date, source revision, device/iOS version, backend/model,
+observed result and supporting logs. Leave unchecked items unqualified; installing
+the app or passing a simulator state test is not equivalent to hearing a reply.
 
 ## 1. Mic input with real speech
 
@@ -21,7 +28,7 @@ ensure the server cert pin is current (see README — re-export after any server
 
 - [ ] While the agent is speaking, start talking → conversation continues without a
     "barge-in" glitch; state returns to listening/thinking as expected.
-- [ ] Text mode: barge-in hint line visible while in text mode.
+- [ ] Switching to Type leaves microphone capture off and text messaging usable.
 
 ## 3. Wake lock (screen off)
 
@@ -39,8 +46,8 @@ ensure the server cert pin is current (see README — re-export after any server
 ## 5. Mic permission denied fallback
 
 - [ ] Deny microphone permission in iOS Settings for the app, relaunch.
-- [ ] Start → session reaches **ready** despite mic failure (non-fatal); orange error
-    banner shows the mic error; text mode remains fully usable.
+- [ ] Start → session reaches **ready** despite mic failure (non-fatal); a visible
+    error explains the problem and offers iPhone Settings recovery; Type remains usable.
 
 ## 6. General device sanity