feat!: remove the old API, ports 8081 and 8080 (step 4a)

Step 4a of docs/SECURITY_PLAN.md. Port 80 keeps the eleven HTTP routes of
ADR 0006 and the socket at /ws; everything else moved to protocol 2.

- Port 8081 (ApiRoutes) and the socket on 8080 (SocketEmitter) are gone.
  Protocol 2 owns its frame buffer and loop-task check.
- Port 80 drops every route the old web UI called: reads, edits,
  settings, scans, reboot, /shades.cfg, /discovery. HttpRoutes.cpp holds
  what stays.
- ModelSnapshot, SnapshotSlots and the read documents are gone. The item
  snapshot types stay, as ItemSnapshot, for events, MQTT and the command
  replies.
- Model edits reply only to their protocol 2 op: requestResult goes.
- The settings' toJSON writers, used only by the settings routes, go.
- The _espsomfy_rts._tcp mDNS record moves to port 80, with path=/ws.
- The memory event reports the loop-rate window it closes.
- A deleted room no longer re-publishes its retained MQTT topics.
- e2e: the heap check reads the sync's status; the sync is checked on
  its own instead of against /controller.
- README gets an API and ports section.

BREAKING CHANGE: ports 8081 and 8080 and the old HTTP routes are gone.
Home Assistant needs integration 3.0.0 or newer.

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

src/SomfyController.cpp

@@ -5,7 +5,6 @@
 #include "ConfigSettings.h"
 #include "ESPNetwork.h"
 #include "entryPoints/Web.h"
-#include "outputs/SocketEmitter.h"
 #include "outputs/ProtoSocket.h"
 #include "Utils.h"
 #include "Somfy.h"
@@ -13,7 +12,6 @@
 #include "LoopQueue.h"
 #include "ShadeRequests.h"
 #include "SomfyShadeOps.h"
-#include "ModelSnapshot.h"
 #include "esp_core_dump.h"
 #include "esp_system.h"
 #include "esp_app_desc.h"
@@ -40,7 +38,6 @@ static bool otaPending = false;
 
 ConfigSettings settings;
 Web webServer;
-SocketEmitter sockEmit;
 ESPNetwork net;
 rebootDelay_t rebootDelay;
 SomfyShadeController somfy;
@@ -48,7 +45,6 @@ MqttConnection mqtt;
 SomfyShadeOps shadeOps;
 ShadeRequests shadeRequests(shadeOps);
 LoopQueue loopQueue;
-SnapshotSlots snapshotSlots;
 LoopStats loopStats;
 
 uint32_t oldheap = 0;
@@ -187,7 +183,6 @@ void loop() {
     webServer.loop();
     logIfSlow(TAG, "Loop web server", timing.lap(), LOOP_SLOW_MS);
     esp_task_wdt_reset();
-    sockEmit.loop();
     protoSocket.loop();
     logIfSlow(TAG, "Loop sockets", timing.lap(), LOOP_SLOW_MS);
     esp_task_wdt_reset();