fix(search): trim leading aesthetic punctuation in artist lookups

Artists like ".diedlonely" (leading dot, †, ✝, _ …) weren't surfaced by iTunes,
so the download's metadata lookup fell through to a titleOnly match — grabbing a
same-titled track by another artist (e.g. the "In the Bleak Midwinter" Christmas
carol: Holiday genre, 176s single) and steering the YouTube search to the wrong
(slowed) version.

- backend/metadata.js: strip leading non-alphanumeric from the search artist and
  the first-word comparison so the real artist matches (and the right album/genre/
  duration are used).
- android ExploreViewModel: strip leading symbols from the search term so the
  Explore tab finds these artists.

Keeps the original name for display/storage — only the search/compare is trimmed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

android/app/src/main/kotlin/com/novasonic/app/viewmodel/ExploreViewModel.kt

@@ -102,10 +102,13 @@ class ExploreViewModel(app: Application) : AndroidViewModel(app) {
     }
 
     private fun search(q: String) {
+        // Strip leading aesthetic punctuation (".diedlonely", "†…") so iTunes actually surfaces the
+        // artist instead of nothing. Falls back to the raw query if it was only symbols.
+        val term = q.trimStart { !it.isLetterOrDigit() }.trim().ifBlank { q }
         viewModelScope.launch {
             _state.value = _state.value.copy(isSearching = true, error = null)
             try {
-                val resp = ItunesClient.search(q)
+                val resp = ItunesClient.search(term)
                 val results = resp.results
                 _state.value = _state.value.copy(
                     artists    = results.filter { it.wrapperType == "artist" },