fix: restore hassfest and Home Assistant CI

## Summary
- fix hassfest validation by replacing raw options-description URLs with Home Assistant translation placeholders
- extend the pytest CI matrix to cover the latest patch release for each Home Assistant month, plus dev
- align CI/dev container Python versions and tests with newer Home Assistant behavior

## Validation
- GitHub Actions pytest matrix passed for 2024.12.5 through 2026.4.3 plus dev
- Docker passed for linux/amd64 and linux/arm64
- hassfest, HACS validation, pre-commit, pre-commit.ci, markdown-code-runner, docs build, and Release Drafter passed

scripts/setup-dependencies

@@ -9,6 +9,30 @@ sed -i '/^mypy-dev/d' core/requirements_test.txt
 
 uv pip install -r core/requirements.txt
 uv pip install -r core/requirements_test.txt
+
+# HA 2026.4+ imports aiohasupervisor from tests/components/conftest.py
+# but pins it in requirements_test_all.txt instead of requirements_test.txt.
+aiohasupervisor_req=""
+if [[ -f core/requirements_test_all.txt ]]; then
+  aiohasupervisor_req="$(grep -m1 '^aiohasupervisor' core/requirements_test_all.txt || true)"
+fi
+if [[ -n "${aiohasupervisor_req}" ]]; then
+  uv pip install "${aiohasupervisor_req}"
+fi
+
+# HA 2026.4+ validates service translations through translations/en.json.
+# The core checkout keeps English source strings in strings.json, so seed en.json
+# in the temporary CI checkout before tests load integrations.
+for strings_file in core/homeassistant/components/*/strings.json; do
+  [[ -f "${strings_file}" ]] || continue
+  translations_dir="$(dirname "${strings_file}")/translations"
+  en_translation="${translations_dir}/en.json"
+  if [[ ! -f "${en_translation}" ]]; then
+    mkdir -p "${translations_dir}"
+    cp "${strings_file}" "${en_translation}"
+  fi
+done
+
 uv pip install -e core/
 uv pip install ulid-transform # this is in Adaptive-lighting's manifest.json
 uv pip install $(python test_dependencies.py)

scripts/setup-devcontainer

@@ -15,7 +15,7 @@ pip install \
 
 pip cache purge
 
-uv venv --clear --python 3.13
+uv venv --clear --python 3.14.2
 ./scripts/setup-dependencies
 ./scripts/setup-symlinks
 uv run pre-commit install-hooks

scripts/update-test-matrix.py

@@ -82,9 +82,13 @@ def get_python_version(ha_version: str) -> str:
     """Determine Python version based on HA Core version."""
     parts = ha_version.split(".")
     year, month = int(parts[0]), int(parts[1])
-    # 2024.x and 2025.1 use Python 3.12, 2025.2+ use Python 3.13
+    # 2024.x and 2025.1 use Python 3.12.
+    # 2025.2 through 2026.2 use Python 3.13.
+    # 2026.3+ uses Python 3.14.
     if year == 2024 or (year == 2025 and month == 1):
         return "3.12"
+    if year > 2026 or (year == 2026 and month >= 3):
+        return "3.14.2"
     return "3.13"
 
 
@@ -97,7 +101,7 @@ def generate_matrix_yaml(versions: list[str]) -> str:
         lines.append(f'            python-version: "{python_ver}"')
     # Add dev version
     lines.append('          - core-version: "dev"')
-    lines.append('            python-version: "3.13"')
+    lines.append('            python-version: "3.14.2"')
     return "\n".join(lines)