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

custom_components/dkncloudna/coordinator.py

@@ -12,7 +12,13 @@ from homeassistant.exceptions import ConfigEntryAuthFailed
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
 
 from .api import DknAuthError, DknCloudNaClient, DknConnectionError
-from .const import CONF_REFRESH_TOKEN, CONF_USER_TOKEN, DEFAULT_SCAN_INTERVAL, DOMAIN, LOGGER
+from .const import (
+    CONF_REFRESH_TOKEN,
+    CONF_USER_TOKEN,
+    DEFAULT_SCAN_INTERVAL,
+    DOMAIN,
+    LOGGER,
+)
 
 
 class DknCoordinator(DataUpdateCoordinator[dict[str, dict[str, Any]]]):
@@ -34,6 +40,7 @@ class DknCoordinator(DataUpdateCoordinator[dict[str, dict[str, Any]]]):
         entry: ConfigEntry,
         client: DknCloudNaClient,
     ) -> None:
+        """Initialise the coordinator with the entry's scan interval."""
         scan_interval = int(entry.options.get("scan_interval", DEFAULT_SCAN_INTERVAL))
         super().__init__(
             hass,
@@ -66,7 +73,7 @@ class DknCoordinator(DataUpdateCoordinator[dict[str, dict[str, Any]]]):
             raise UpdateFailed(f"Cannot reach DKN Cloud NA: {err}") from err
         except asyncio.CancelledError:
             raise
-        except Exception as err:  # noqa: BLE001
+        except Exception as err:
             raise UpdateFailed(f"Unexpected error: {type(err).__name__}") from err
 
         self._persist_tokens_if_changed()