[bluetooth_connection] Move BluetoothConnection out of bluetooth_proxy (#18129)

tests/component_tests/bluetooth_proxy/test_platform_gates.py

@@ -5,12 +5,12 @@ advertisement-only arm applies its own defaults."""
 import pytest
 
 from esphome import config_validation as cv
-from esphome.components import bluetooth_proxy
+from esphome.components import bluetooth_connection, bluetooth_proxy
 from esphome.const import CONF_ACTIVE, KEY_TARGET_PLATFORM
 from esphome.core import CORE, KEY_CORE
 
 
-def _set_platform(platform: str) -> None:
+def _set_platform(platform: str | None) -> None:
     CORE.data.setdefault(KEY_CORE, {})[KEY_TARGET_PLATFORM] = platform
 
 
@@ -46,3 +46,17 @@ def test_hub_platform_accepts_the_advertisement_only_shape() -> None:
     _set_platform("ln882x")
     validated = bluetooth_proxy.CONFIG_SCHEMA({})
     assert validated[CONF_ACTIVE] is False
+
+
+def test_bluetooth_connection_auto_load_covers_its_includes() -> None:
+    # The esp32 connection header includes esp32_ble_client; the auto load
+    # must satisfy that closure itself (regression: it once relied on the
+    # consumer's auto loads).
+    _set_platform("esp32")
+    assert "esp32_ble_client" in bluetooth_connection.AUTO_LOAD()
+    _set_platform("rp2")
+    assert bluetooth_connection.AUTO_LOAD() == ["ble_device_base"]
+    # No target platform (tooling resolving the manifest): the union, so
+    # dependency closures stay complete for build_codeowners and friends.
+    _set_platform(None)
+    assert bluetooth_connection.AUTO_LOAD() == ["ble_device_base", "esp32_ble_client"]