[network] Fix logged use_address with MAC suffix and build it at runtime

tests/integration/fixtures/use_address_runtime.yaml

@@ -0,0 +1,8 @@
+esphome:
+  name: use-address-runtime
+
+host:
+
+api:
+
+logger:

tests/integration/fixtures/use_address_runtime_mac_suffix.yaml

@@ -0,0 +1,9 @@
+esphome:
+  name: use-address-mac
+  name_add_mac_suffix: true
+
+host:
+
+api:
+
+logger:

tests/integration/test_use_address_runtime.py

@@ -0,0 +1,73 @@
+"""Integration tests for the runtime-built use_address.
+
+The default "<name>.local" address is no longer stored as a compile-time string;
+it is built at runtime from the device name. This also fixes the logged address
+when name_add_mac_suffix is enabled: the baked string used to miss the MAC
+suffix, so it never matched the actual mDNS hostname.
+"""
+
+from __future__ import annotations
+
+import asyncio
+
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+# Host platform default MAC: 98:35:69:ab:f6:79 -> suffix "abf679"
+MAC_SUFFIX = "abf679"
+
+
+@pytest.mark.asyncio
+async def test_use_address_runtime(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """The API dump_config logs "<name>.local" built from the device name."""
+    address_seen = asyncio.Event()
+
+    def check_output(line: str) -> None:
+        if "Address: use-address-runtime.local:" in line:
+            address_seen.set()
+
+    async with (
+        run_compiled(yaml_config, line_callback=check_output),
+        api_client_connected() as client,
+    ):
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == "use-address-runtime"
+
+        try:
+            await asyncio.wait_for(address_seen.wait(), timeout=10.0)
+        except TimeoutError:
+            pytest.fail("Did not log 'Address: use-address-runtime.local:'")
+
+
+@pytest.mark.asyncio
+async def test_use_address_runtime_mac_suffix(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """With name_add_mac_suffix the logged address includes the MAC suffix."""
+    address_seen = asyncio.Event()
+    expected = f"Address: use-address-mac-{MAC_SUFFIX}.local:"
+
+    def check_output(line: str) -> None:
+        if expected in line:
+            address_seen.set()
+
+    async with (
+        run_compiled(yaml_config, line_callback=check_output),
+        api_client_connected() as client,
+    ):
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == f"use-address-mac-{MAC_SUFFIX}"
+
+        try:
+            await asyncio.wait_for(address_seen.wait(), timeout=10.0)
+        except TimeoutError:
+            pytest.fail(f"Did not log '{expected}'")