fix: replace deprecated get_astral_location with get_astral_observer (#1482)

* fix: replace deprecated get_astral_location with get_astral_observer (#1481)

HA 2026.7 deprecates homeassistant.helpers.sun.get_astral_location
(removal planned for 2027.7) in favor of get_astral_observer, causing a
deprecation warning in the HA logs.

- Switch SunEvents/SunLightSettings from astral.location.Location to
  astral.Observer, using the astral.sun module functions (which return
  UTC times by default, matching the previous local=False calls).
- Use get_astral_observer in switch.py, with a fallback for HA < 2026.7
  that constructs the Observer directly from the HA config.
- Update tests and the webapp simulator accordingly.

* ci: handle removal of requirements_test_all.txt in HA 2026.8 dev

HA core removed requirements_test_all.txt (home-assistant/core#171530),
which made test_dependencies.py crash with FileNotFoundError and broke
the dev pytest job and the Docker builds. Fall back to
requirements_all.txt, which carries the same per-integration
'# homeassistant.components.x' annotations. Also extend the
aiohasupervisor pin lookup in scripts/setup-dependencies accordingly.

* test: support modern template light config for HA 2026.6+

HA 2026.6 removed the legacy `light: platform: template` YAML format
(home-assistant/core#169615), so setup_lights found no template platform
on HA dev and every test using it failed with IndexError. Detect legacy
support at runtime (PLATFORM_SCHEMA presence) and fall back to the
modern `template:` config format. The group platform is set up before
the template integration in the modern path, because setting up
`template` also sets up the `light` domain, which would make a later
async_setup_component(hass, LIGHT_DOMAIN, ...) a no-op.

webapp/app.py

@@ -8,8 +8,7 @@ from typing import Any
 import matplotlib.pyplot as plt
 import numpy as np
 import shinyswatch
-from astral import LocationInfo
-from astral.location import Location
+from astral import Observer
 from homeassistant_util_color import color_temperature_to_rgb
 from shiny import App, render, ui
 
@@ -298,7 +297,6 @@ def time_to_float(time: dt.time | dt.datetime) -> float:
 
 
 def _kw(input):
-    location = Location(LocationInfo(timezone=dt.timezone.utc))
     return {
         "name": "Adaptive Lighting Simulator",
         "adapt_until_sleep": input.adapt_until_sleep(),
@@ -324,8 +322,8 @@ def _kw(input):
         "max_sunrise_time": None,
         "min_sunset_time": None,
         "max_sunset_time": None,
-        "astral_location": location,
-        "timezone": location.timezone,
+        "astral_observer": Observer(),
+        "timezone": dt.timezone.utc,
     }