chore: drop HACS distribution and move CI to Gitea

The GitHub mirror is gone, so the HACS packaging and the GitHub-only CI
no longer have anything to run against.

Remove hacs.json and the .github/ workflow. Both of its jobs (hassfest
and hacs/action) were gated on `github.server_url == 'https://github.com'`
and are GitHub-hosted actions, so neither can run on the Gitea runner.

Replace them with .gitea/workflows/ci.yml:
  - lint: ruff check + ruff format --check, version pinned because ruff's
    default rule set and formatter output move between releases
  - validate: byte-compile, then scripts/validate_integration.py, which
    covers the part of hassfest that matters for a manually installed
    custom component (manifest keys, domain/directory agreement, and
    translations matching strings.json key for key)

README now documents manual installation only, and points at the local
CI commands. manifest.json documentation and issue_tracker point at the
Gitea repo; NOTICE keeps its upstream attribution.

Adopting ruff surfaced two real defects, fixed here:
  - climate.async_set_hvac_mode raised HomeAssistantError for an
    unsupported mode from inside a try that catches Exception, so the
    message was re-wrapped as "Failed to set HVAC mode: Unsupported HVAC
    mode: ...". The validation is now hoisted above the try.
  - config_flow.async_step_reauth_confirm swallowed unexpected exceptions
    into a bare "unknown" error with no log, unlike the user step. It now
    logs via _LOGGER.exception.

Remaining changes are mechanical: import ordering, docstrings on public
methods, ClassVar on mutable class attributes, contextlib.suppress, and
asyncio.TimeoutError -> TimeoutError (an alias since 3.11). The smoke
test now reads the new DknCloudNaClient.socket_connected property rather
than reaching into _socket.

Co-authored-by: anthropic/claude-opus-5

README.md

@@ -1,11 +1,8 @@
 # DKN Cloud NA — Home Assistant Integration
 
-[![HACS][hacs-badge]][hacs-url]
-[![Validate][validate-badge]][validate-url]
-
 Control your Daikin mini-split air conditioners through Home Assistant using the DKN Cloud NA cloud service.
 
-This integration is a port of the [homebridge-dkncloudna](https://github.com/plecong/homebridge-dkncloudna) plugin by [@plecong](https://github.com/plecong), adapted for Home Assistant and distributed via HACS.
+This integration is a port of the [homebridge-dkncloudna](https://github.com/plecong/homebridge-dkncloudna) plugin by [@plecong](https://github.com/plecong), adapted for Home Assistant.
 
 ---
 
@@ -20,24 +17,18 @@ Any Daikin mini-split system connected to the **DKN Cloud NA** WiFi adapter (Nor
 - A working [DKN Cloud NA](https://dkncloudna.com) account
 - Your Daikin unit(s) already set up and visible in the DKN Cloud NA app
 - Home Assistant 2024.1 or later
-- HACS 2.0 or later
 
 ---
 
 ## Installation
 
-### Via HACS (recommended)
+This integration is installed manually — it is not published to HACS.
 
-1. Open HACS in your Home Assistant instance
-2. Go to **Integrations**
-3. Click the **⋮** menu → **Custom repositories**
-4. Add `https://github.com/thatguygriff/homeassistant-dkncloudna` as an **Integration**
-5. Search for **DKN Cloud NA** and install it
-6. Restart Home Assistant
+1. Download or clone this repository
+2. Copy the `custom_components/dkncloudna/` directory into your Home Assistant `config/custom_components/` directory, so that you end up with `config/custom_components/dkncloudna/manifest.json`
+3. Restart Home Assistant
 
-### Manual
-
-Copy the `custom_components/dkncloudna/` directory into your Home Assistant `config/custom_components/` directory and restart.
+To upgrade, replace the `dkncloudna` directory with the newer copy and restart again.
 
 ---
 
@@ -84,12 +75,29 @@ Each device exposes the following entities:
 
 ---
 
+## Development
+
+CI runs on Gitea Actions (`.gitea/workflows/ci.yml`). To reproduce it locally:
+
+```sh
+pip install ruff==0.16.8       # version is pinned in CI
+ruff check .
+ruff format --check .
+python3 scripts/validate_integration.py
+```
+
+`scripts/validate_integration.py` checks that every JSON file parses, that
+`manifest.json` has the keys Home Assistant requires of a custom integration,
+and that each file in `translations/` has the same key structure as
+`strings.json`.
+
+`smoke-test/run.sh` exercises the client against a real DKN Cloud NA account.
+It needs a `.env` with `DKN_CLOUD_NA_EMAIL` and `DKN_CLOUD_NA_PASSWORD` (see
+`.env.example`) and is run by hand, not in CI.
+
+---
+
 ## Credits
 
 - Original Homebridge plugin: [homebridge-dkncloudna](https://github.com/plecong/homebridge-dkncloudna) by [@plecong](https://github.com/plecong)
 - EU counterpart inspiration: [DKNCloud-HASS](https://github.com/eXPerience83/DKNCloud-HASS) by [@eXPerience83](https://github.com/eXPerience83)
-
-[hacs-badge]: https://img.shields.io/badge/HACS-Custom-orange.svg
-[hacs-url]: https://github.com/hacs/integration
-[validate-badge]: https://github.com/lavoiesl/homeassistant-dkncloudna/actions/workflows/validate.yml/badge.svg
-[validate-url]: https://github.com/lavoiesl/homeassistant-dkncloudna/actions/workflows/validate.yml