Add HACS publish workflows and README HACS badge

Author: javaDevJT

.github/workflows/hacs.yaml

@@ -0,0 +1,17 @@
+name: HACS Validation
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  hacs:
+    name: HACS
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: HACS validation
+        uses: hacs/action@main
+        with:
+          category: integration

.github/workflows/hassfest.yaml

@@ -0,0 +1,15 @@
+name: Hassfest
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  hassfest:
+    name: Hassfest
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Hassfest validation
+        uses: home-assistant/actions/hassfest@master

README.md

@@ -2,6 +2,7 @@
 
 [![Website](https://img.shields.io/badge/Website-javadevjt.tech-0A66C2?logo=googlechrome&logoColor=white)](https://javadevjt.tech)
 [![Buy%20Me%20a%20Coffee](https://img.shields.io/badge/Buy%20Me%20a%20Coffee-javadevjt-FFDD00?logo=buymeacoffee&logoColor=000000)](https://buymeacoffee.com/javadevjt)
+[![Open in HACS](https://my.home-assistant.io/badges/hacs_repository.svg)](https://my.home-assistant.io/redirect/hacs_repository/?owner=javaDevJT&repository=DTE-Rates-for-Home-Assistant&category=integration)
 
 A Home Assistant custom integration that pulls the official DTE residential electric rate card PDF, parses rates dynamically, and exposes import/export price entities that track time-of-day and season.