Group 7: tests — 94 passing in 0.57s (53/53 + 9.4 deferred)

Test infrastructure:
- Add `pytest-homeassistant-custom-component` (PHACC) as a `test`
  dependency group. PHACC ships `hass`, `enable_custom_integrations`,
  `MockConfigEntry`, and friends without needing to clone HA core as a
  sibling directory. Modernizes the test setup from upstream's
  `setup-symlinks` pattern.
- conftest.py: add `auto_enable_custom_integrations` autouse fixture
  so HA discovers the integration under `custom_components/` during
  tests. Keep the upstream template-deprecation no-op.
- Import paths: all tests now import from `custom_components.adaptive_lighting`
  (not `homeassistant.components.adaptive_lighting`) and from
  `pytest_homeassistant_custom_component.common` (not `tests.common`).

New tests (groups 7.2-7.16):
- tests/test_color_and_brightness.py (16 tests): TestBrightnessCurve
  asserts min-before-sunrise, midpoint-at-event, max-during-day, sunset
  ramp symmetry. TestColorTempCurve verifies the same shape applies to
  K. TestSunPosition checks the synthetic +1/-1/0 derivation.
  TestTanhDayCurveDirect exercises the helper directly.
- tests/test_config_flow.py (12 tests): six sections in order, each
  section contains only its specified fields, conditional visibility
  of send_split_delay, default sun entities, strict-typed entity
  selectors, NumberSelector slider/box configs, BooleanSelector for
  every flag, full user→create-entry flow, YAML-managed entry aborts
  with `yaml_managed` reason, options flow renders the sectioned schema.
- tests/test_init.py (6 tests): successful setup on current version,
  stale version raises ConfigEntryError via async_migrate_entry,
  unload is clean, tombstone removes orphan sleep entity + logs INFO,
  tombstone is idempotent, tombstone respects config_entry ownership.

Source modernizations driven by the tests:
- __init__.py: add `async_migrate_entry` that surfaces the
  "incompatible — delete and recreate" message and sets the entry to
  MIGRATION_ERROR. Removed direct `ConfigEntryError` from
  `async_setup_entry` (HA routes version mismatches through the
  migration handler now).
- switch.py: removed upstream's YAML-managed-entry auto-remove hack.
  YAML profiles now load normally and the options flow handles the
  "you must edit configuration.yaml" message (spec R7).

Existing tests updated to PHACC paths: test_adaptation_utils.py
(38 tests), test_hass_utils.py (22 tests). Both pass without
modification beyond the import fix.

Deleted: tests/test_switch.py (2,999 LOC of upstream tests, most
covering sleep mode / take-over-control / manual-control state
machines that no longer exist; CDiT-specific switch tests deferred
to a follow-up change).

Result: `uv run --group test pytest tests/` → 94 passed in 0.57s.

Deferred from this change:
- 4.3: manual UI test that toggling a field and saving reloads cleanly
  (requires a real HA instance, can't be done from CLI).
- 9.4: GitHub repo description / topics update (do via `gh repo edit`
  outside the change scope).

openspec status: 4/4 artifacts complete; strict-validate green.

tests/conftest.py

@@ -1,4 +1,9 @@
-"""Pytest configuration for adaptive-lighting tests."""
+"""Pytest configuration for Adaptive Lighting tests (CDiT fork).
+
+Uses `pytest-homeassistant-custom-component` (PHACC). The
+`enable_custom_integrations` fixture lets HA discover and load this
+integration from `custom_components/` during tests.
+"""
 
 from unittest.mock import patch
 
@@ -6,21 +11,24 @@ import pytest
 
 
 @pytest.fixture(autouse=True)
-def mock_template_deprecation_issue():
-    """Mock the template deprecation issue creation.
+def auto_enable_custom_integrations(enable_custom_integrations):
+    """PHACC requires this fixture to be active for HA to find the
+    integration under custom_components/."""
+    yield
 
-    The template component's legacy platform syntax creates deprecation
-    issues that require translations. Since adaptive-lighting tests use
-    template lights as test fixtures (not testing the template integration
-    itself), we mock the issue creation to avoid translation validation errors.
+
+@pytest.fixture(autouse=True)
+def mock_template_deprecation_issue():
+    """Mock the template helpers' legacy deprecation-issue creation.
+
+    Template lights used as fixtures in upstream tests trigger a
+    deprecation-issue call that requires translation entries we don't ship.
+    No-op the call so tests don't fail on translation validation.
     """
-    # Patch the create_legacy_template_issue function in the template helpers
-    # to be a no-op when called for the deprecated_legacy_templates issue
     try:
         with patch(
             "homeassistant.components.template.helpers.create_legacy_template_issue",
         ):
             yield
     except (ImportError, ModuleNotFoundError, AttributeError):
-        # Older HA versions don't have this function
         yield