Move backend files to root level for cleaner GitHub display

- Move all backend files from swingmusic/ to root level
- Backend files now display directly on GitHub repository page
- Keep client applications as submodules (swingmusic-android, swingmusic-desktop, swingmusic-webclient)
- Update README to reflect new structure (no cd swingmusic needed)
- Cleaner, more professional GitHub repository layout

Files moved to root:
- src/ (main source code)
- pyproject.toml, requirements.txt, run.py
- swingmusic.spec, uv.lock, version.txt
- services/

Result: GitHub shows backend files directly while maintaining organized structure

src/swingmusic/setup/__init__.py

@@ -0,0 +1,55 @@
+"""
+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

@@ -0,0 +1,37 @@
+"""
+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()