say what this plugin is for, in the store's words

tags are how the marketplace is browsed rather than scrolled: a list of them on
the left, the plugins that carry one on the right. a closed vocabulary
(PLUGIN_TAGS in the platform) because free text becomes homelab, home-lab, Home
Lab and selfhosted inside a month, and a filter list of synonyms is worse than
no filter at all.

declared here rather than curated in the catalogue, so a plugin can say what it
is and nobody edits a table when one ships. the marketplace caches it on sync,
exactly as it already does for label and summary.

manifest.ts

@@ -45,6 +45,8 @@ export const manifest: PluginManifest = {
 
   label: 'Music',
   summary: 'The music library — browse, play, favourites and playlists',
+  /** your own library. */
+  tags: ['Homelab', 'Personal'],
   // No `icon` field: this plugin ships `assets/icon.png` and the file wins. A lucide name could only
   // ever pick from the 106 glyphs the platform happens to bundle, which is a ceiling a plugin from a
   // marketplace cannot see coming — and this one's artwork is a voxel duck in headphones, not a glyph.