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/setup/__init__.py

@@ -1,55 +0,0 @@
-"""
-Prepares the server for use.
-"""
-
-from time import time
-import uuid
-from swingmusic.lib.mapstuff import (
-    map_album_colors,
-    map_artist_colors,
-    map_favorites,
-    map_scrobble_data,
-)
-from swingmusic.setup.sqlite import run_migrations, setup_sqlite
-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.generators import get_random_str
-
-from swingmusic.config import UserConfig
-from dataclasses import asdict
-
-
-def run_setup():
-    """
-    Creates the config directory, runs migrations, and loads settings.
-    """
-
-    # setup config file
-    config = UserConfig()
-    config.setup_config_file()
-
-    if not config.serverId:
-        config.serverId = str(uuid.uuid4())
-        config.write_to_file(asdict(config))
-
-    setup_sqlite()
-    run_migrations()
-
-
-def load_into_mem():
-    """
-    Load all tracks, albums, and artists into memory.
-    """
-    # INFO: Load all tracks, albums, and artists data into memory
-    key = str(time())
-    TrackStore.load_all_tracks(get_random_str())
-    AlbumStore.load_albums(key)
-    ArtistStore.load_artists(key)
-    FolderStore.load_filepaths()
-
-    map_scrobble_data()
-    map_favorites()
-    map_artist_colors()
-    map_album_colors()

src/swingmusic/setup/sqlite.py

@@ -1,37 +0,0 @@
-"""
-Module to setup Sqlite databases and tables.
-Applies migrations.
-"""
-
-from sqlalchemy import create_engine
-from swingmusic.db.userdata import UserTable
-from swingmusic.migrations import apply_migrations
-from swingmusic.settings import Paths
-
-from swingmusic.db.engine import DbEngine
-from swingmusic.db import create_all_tables
-
-
-def run_migrations():
-    """
-    Run migrations and updates migration version.
-    """
-    apply_migrations()
-
-
-def setup_sqlite():
-    """
-    Create Sqlite databases and tables.
-    """
-    DbEngine._engine = create_engine(
-        f"sqlite+pysqlite:///{Paths().app_db_path}",
-        echo=False,
-        max_overflow=20,
-        pool_size=10,
-    )
-
-    create_all_tables()
-    # create_user_tables()
-
-    if not list(UserTable.get_all()):
-        UserTable.insert_default_user()