Add M3U Lint action

.forgejo/workflows/validate.yaml

@@ -0,0 +1,24 @@
+name: M3U Lint
+
+on:
+  push:
+    paths:
+      - 'mystique.m3u'
+
+jobs:
+  lint:
+    runs-on: docker
+    
+    steps:
+      - uses: actions/checkout@v4
+      
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          
+      - name: Install m3u-linter
+        run: npm install -g m3u-linter
+        
+      - name: Run M3U linter
+        run: m3u-linter mystique.m3u