feat: Rename game to soundtrack throughout codebase

- Database migration: rename game table to soundtrack
- Rename game_name to soundtrack_name, game_id to soundtrack_id
- Update all SQL queries in soundtrack.sql, song.sql, song_list.sql, statistics.sql
- Regenerate sqlc code (soundtrack.sql.go, song.sql.go, etc.)
- Update backend: music.go, sync.go, statistics.go
- Update server: musicHandler.go, syncHandler.go, routes.go
- Update frontend: hello.go
- Keep URL paths as /games for backward compatibility

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

cmd/web/hello.go

@@ -30,7 +30,7 @@ func FindGameWebHandler(w http.ResponseWriter, r *http.Request) {
 
 func search(searchText string) {
 	games_added = nil
-	games := backend.GetAllGames()
+	games := backend.GetAllSoundtracks()
 	for _, game := range games {
 		if is_match_exact(searchText, game) {
 			add_game(game)