refactor(tooling): [MOD-PLUGIN-01] generate typed plugins with safe output handling

scripts/plugin/template/src/stylesheet.ts.tpl

@@ -0,0 +1,12 @@
+import css from './style.less?inline'
+
+// The stylesheet belongs to the module, not individual player instances.
+if (typeof document !== 'undefined') {
+  const id = 'artplayer-plugin-{{name}}'
+  if (!document.getElementById(id)) {
+    const style = document.createElement('style')
+    style.id = id
+    style.textContent = css
+    ;(document.head || document.documentElement).appendChild(style)
+  }
+}