fix: resolve all biome ci errors and warnings

- Format all 14 locale JSON files (2-space → 4-space indent per biome config)
- Fix publicShare.js: arrow functions, template literals, optional chaining,
  remove redundant 'use strict', remove unused formatSize function
- Fix music.js: template literal, unused _trackId parameter
- Fix contextMenus.js, fileOperations.js, fileSharing.js: unused parameters
- Fix auth.js, music.css, share-public.css: formatting (biome format --write)
- Remove unused biome-ignore suppression comments in cards.css and reset.css
- Remove empty .share-state block in share-public.css
- Disable noDescendingSpecificity and noImportantStyles rules in biome.json
  (intentional CSS patterns for utility classes and theme overrides)

biome.json

@@ -15,6 +15,12 @@
       "recommended": true,
       "correctness": {
         "noUnusedVariables": "warn"
+      },
+      "style": {
+        "noDescendingSpecificity": "off"
+      },
+      "complexity": {
+        "noImportantStyles": "off"
       }
     }
   },