other domain than .local

**Describe the problem you have/What new integration you would like**

ESPHome currently relies on mDNS for device discovery, using .local hostnames. However, some networks do not support mDNS, making it impossible to resolve ESPHome nodes without manually configuring static IP addresses. I would like ESPHome to support specifying a custom domain name that can be resolved via traditional DNS.

**Please describe your use case for this integration and alternatives you've tried:**

In my network, mDNS is not available, but I have a DNS server that can resolve FQDNs (e.g., node-terrasse.mydomain.com). Currently, I have to manually enter static IP addresses within "wifi -> manual_ip" for each single device, which is not ideal for dynamic or large-scale deployments. An option to configure a custom FQDN instead of .local would improve usability in environments where mDNS is not available.

**Additional context**

Ideally, this could be implemented as a configuration option in ESPHome global configuration like status_use_ping, allowing users to specify a custom hostname for OTA updates and dashboard communication. Some users rely on DHCP reservations instead of static IPs, so allowing a hostname that DNS can resolve dynamically would be beneficial. This would improve ESPHome’s compatibility with corporate and enterprise networks that do not use mDNS.

Start by reviewing ESPHome’s global configuration and the existing mDNS-based device discovery, OTA update, and dashboard communication described in the request. Define how a custom DNS-resolvable FQDN should be configured and used instead of a .local hostname, then verify behavior on networks without mDNS and with DHCP-assigned addresses.

Written by the indexing model from the issue text.