fix: review fixes for step 4a

- e2e: the heap check uses a socket slot now, so it waits for the device
  to free it, and test_every_client_reconnecting_at_once closes its
  clients before the check runs.
- Comments and docs that still named removed things (the /controller read,
  the event buffer, memStatus, SocketEmitter, ModelSnapshot).
- ESPNetwork::emitSockets is emitStatus: one socket, and it sends the status.
- Unused includes, whitespace-only lines left by the toJSON removal.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/SomfyController.cpp

@@ -155,7 +155,7 @@ void setup() {
 void loop() {
   // put your main code here, to run repeatedly:
   //uint32_t heap = ESP.getFreeHeap();
-  // Times the whole pass for memStatus, including any time the loop task was
+  // Times the whole pass for the memory event, including any time the loop task was
   // pre-empted, since that delays the loop too.
   ElapsedTimer pass;
   if(rebootDelay.reboot && millis() > rebootDelay.rebootTime) {