Address review: slot-cap testing mode, derived source filter, breadcrumbs

- Skip the hub-platform GATT slot cap in testing mode (mirrors
  esp32_ble.validate_connection_slots) so grouped builds validate
- Derive the neutral engine's source filter from the backend registry so
  a new platform cannot validate and then fail at link
- Log the real code on refused service discovery and cancelled connects;
  read completions get the same breadcrumb writes have
- Comment accuracy: the dumper arm is the legacy shape, not a superset
- Ledger tests: real-validator end-to-end path and the testing-mode skip

tests/component_tests/bluetooth_connection/test_slot_ledger.py

@@ -3,15 +3,55 @@
 import pytest
 
 from esphome import config_validation as cv
-from esphome.components import bluetooth_connection
-from esphome.const import KEY_CORE, KEY_TARGET_PLATFORM, PLATFORM_RP2
+from esphome.components import (
+    ble_client,
+    ble_device_base,
+    bluetooth_connection,
+    bluetooth_proxy,
+)
+from esphome.const import (
+    CONF_MAC_ADDRESS,
+    KEY_CORE,
+    KEY_TARGET_PLATFORM,
+    PLATFORM_RP2,
+    PlatformFramework,
+)
 from esphome.core import CORE
 
+from ..types import SetCoreConfigCallable
+
 
 def test_gatt_slot_ledger_rejects_overcommit_on_rp2() -> None:
-    # The cross-component cap must reject two claims on rp2.
+    # The cap logic in isolation: two hand charges must trip it.
     CORE.data.setdefault(KEY_CORE, {})[KEY_TARGET_PLATFORM] = PLATFORM_RP2
     bluetooth_connection.consume_gatt_slot("bluetooth_proxy")({})
     bluetooth_connection.consume_gatt_slot("ble_client")({})
     with pytest.raises(cv.Invalid, match="supports at most 1 GATT client"):
         bluetooth_connection.FINAL_VALIDATE_SCHEMA({})
+
+
+def test_gatt_slot_ledger_skipped_in_testing_mode() -> None:
+    # Grouped component builds merge fixtures past the cap; the check defers
+    # to testing mode like esp32_ble.validate_connection_slots.
+    CORE.data.setdefault(KEY_CORE, {})[KEY_TARGET_PLATFORM] = PLATFORM_RP2
+    bluetooth_connection.consume_gatt_slot("bluetooth_proxy")({})
+    bluetooth_connection.consume_gatt_slot("ble_client")({})
+    CORE.testing_mode = True
+    try:
+        bluetooth_connection.FINAL_VALIDATE_SCHEMA({})
+    finally:
+        CORE.testing_mode = False
+
+
+def test_real_validators_charge_the_ledger_on_rp2(
+    set_core_config: SetCoreConfigCallable,
+) -> None:
+    # End to end through the component CONFIG_SCHEMAs (no hand charges):
+    # removing either consumer's consume_gatt_slot call fails this test.
+    set_core_config(PlatformFramework.RP2_ARDUINO)
+    ble_device_base.register_hub_provider("rp2_ble_tracker")
+    CORE.loaded_integrations.add("rp2_ble_tracker")
+    bluetooth_proxy.CONFIG_SCHEMA({})
+    ble_client.CONFIG_SCHEMA({CONF_MAC_ADDRESS: "AA:BB:CC:DD:EE:FF"})
+    with pytest.raises(cv.Invalid, match="requested by: bluetooth_proxy, ble_client"):
+        bluetooth_connection.FINAL_VALIDATE_SCHEMA({})