Support for halow: Component (Wi-Fi HaLow™) for Long-Range ESPHome Devices via SPI

**Describe the problem you have/What new integration you would like**
I would like to propose the development of a `halow:` component in ESPHome to support Wi-Fi HaLow™ (IEEE 802.11ah) modules, such as the Alfa Networks AHST7394S based on the NRC7394 chipset, the Quectel/Silex based on the Morse Micro MM8102/MM6108, or many other modules suppliers with a Halow chip. This component would enable long-range, low-power ESPHome setups using a declarative YAML interface, similar to the existing `wifi:` and `ethernet:` components.

**Please describe your use case for this integration and alternatives you've tried:**
This feature would be especially useful for smart rural and outdoor deployments where long-range, low-power wireless connectivity is needed. Wi-Fi HaLow™ provides significantly better coverage in areas where traditional 2.4/5 GHz Wi-Fi struggles.

There are currently no off-the-shelf options in ESPHome for using HaLow™ over SPI. LoRa, Zigbee, or cellular solutions are alternatives, but each comes with trade-offs in bandwidth, cost, or complexity. HaLow™ offers a clean, IP-native solution—if the ESP-IDF stack can support a SPI interface to the module.

**Additional context**
This feature depends on a lower-level host-side SPI transport driver being developed by Espressif in ESP-IDF. I have submitted a formal request to Espressif for this here:
https://github.com/espressif/esp-idf/issues/16037

Once such a driver is available (likely interfacing via `esp_netif`), ESPHome can build a `halow:` component on top of it, reusing much of the structure from `wifi:` or `ethernet:` components.

Community members interested in contributing or testing this new component are invited to join the discussion. This preparatory request aims to outline feasibility and gather support while the driver layer is under consideration.

A draft architecture and diagram have also been shared to illustrate the stack.


Start by checking the linked ESP-IDF issue 16037 to determine whether the host-side SPI transport driver is available. Then compare the existing ESPHome wifi and ethernet components with the proposed architecture. This work is done when the lower-level transport exists and a halow component can provide the requested declarative interface.

Written by the indexing model from the issue text.