Reorganize repository structure for better organization

- Move backend code to swingmusic/ folder
- Move client applications to root level (swingmusic-android, swingmusic-desktop, swingmusic-webclient)
- Remove intermediate backend/ and clients/ folders
- Update README with new folder structure and setup instructions
- Clean and organized repository layout

src/swingmusic/lib/index.py

@@ -1,43 +0,0 @@
-import gc
-import logging
-from time import time
-from swingmusic.lib.mapstuff import (
-    map_album_colors,
-    map_artist_colors,
-    map_favorites,
-    map_scrobble_data,
-)
-from swingmusic.lib.populate import CordinateMedia
-from swingmusic.lib.recipes.recents import RecentlyAdded
-from swingmusic.lib.tagger import IndexTracks
-from swingmusic.store.albums import AlbumStore
-from swingmusic.store.artists import ArtistStore
-from swingmusic.store.folder import FolderStore
-from swingmusic.store.tracks import TrackStore
-from swingmusic.utils.threading import background
-
-log = logging.getLogger(__name__)
-
-@background
-def index_everything():
-    IndexTracks()
-
-    key = str(time())
-    TrackStore.load_all_tracks(key)
-    AlbumStore.load_albums(key)
-    ArtistStore.load_artists(key)
-    FolderStore.load_filepaths()
-
-    # NOTE: Rebuild recently added items on the homepage store
-    RecentlyAdded()
-
-    # map colors
-    map_album_colors()
-    map_artist_colors()
-
-    map_scrobble_data()
-    map_favorites()
-
-    CordinateMedia(instance_key=str(time()))
-    gc.collect()
-    log.info("Indexing completed")