Add GitHub Actions workflows for HACS validation

Add automated validation workflows for HACS and Hassfest to ensure repository meets quality standards for HACS default store inclusion.

Workflows run on:
- Every push and pull request
- Daily at midnight UTC
- Manual trigger via Actions tab

Validates:
- HACS repository structure and metadata
- Home Assistant integration standards

.github/workflows/validate.yaml

@@ -0,0 +1,29 @@
+name: Validate
+
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
+
+permissions: {}
+
+jobs:
+  validate-hacs:
+    runs-on: "ubuntu-latest"
+    name: Validate with HACS
+    steps:
+      - name: HACS validation
+        uses: "hacs/action@main"
+        with:
+          category: "integration"
+
+  validate-hassfest:
+    runs-on: "ubuntu-latest"
+    name: Validate with Hassfest
+    steps:
+      - name: Checkout code
+        uses: "actions/checkout@v4"
+      - name: Hassfest validation
+        uses: "home-assistant/actions/hassfest@master"