Replace API deferred queue with efficient message batching system (#9012)

tests/integration/fixtures/host_mode_many_entities_multiple_connections.yaml

@@ -0,0 +1,136 @@
+esphome:
+  name: host-mode-many-entities-multi
+  friendly_name: "Host Mode Many Entities Multiple Connections Test"
+
+logger:
+
+host:
+
+api:
+
+sensor:
+  # 20 test sensors for faster testing with multiple connections
+  - platform: template
+    name: "Test Sensor 1"
+    lambda: return 1.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 2"
+    lambda: return 2.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 3"
+    lambda: return 3.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 4"
+    lambda: return 4.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 5"
+    lambda: return 5.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 6"
+    lambda: return 6.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 7"
+    lambda: return 7.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 8"
+    lambda: return 8.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 9"
+    lambda: return 9.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 10"
+    lambda: return 10.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 11"
+    lambda: return 11.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 12"
+    lambda: return 12.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 13"
+    lambda: return 13.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 14"
+    lambda: return 14.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 15"
+    lambda: return 15.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 16"
+    lambda: return 16.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 17"
+    lambda: return 17.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 18"
+    lambda: return 18.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 19"
+    lambda: return 19.0;
+    update_interval: 0.1s
+  - platform: template
+    name: "Test Sensor 20"
+    lambda: return 20.0;
+    update_interval: 0.1s
+
+# Mixed entity types for comprehensive batching test
+binary_sensor:
+  - platform: template
+    name: "Test Binary Sensor 1"
+    lambda: return millis() % 1000 < 500;
+  - platform: template
+    name: "Test Binary Sensor 2"
+    lambda: return millis() % 2000 < 1000;
+
+text_sensor:
+  - platform: template
+    name: "Test Text Sensor 1"
+    lambda: return std::string("Test Value 1");
+  - platform: template
+    name: "Test Text Sensor 2"
+    lambda: return std::string("Test Value 2");
+  - platform: version
+    name: "ESPHome Version"
+
+switch:
+  - platform: template
+    name: "Test Switch 1"
+    lambda: return true;
+    turn_on_action:
+      - logger.log: "Switch 1 ON"
+    turn_off_action:
+      - logger.log: "Switch 1 OFF"
+
+button:
+  - platform: template
+    name: "Test Button"
+    on_press:
+      - logger.log: "Button pressed"
+
+number:
+  - platform: template
+    name: "Test Number"
+    min_value: 0
+    max_value: 100
+    step: 1
+    lambda: return 50.0;
+    set_action:
+      - logger.log: "Number set"