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/enums/album_versions.py

@@ -1,67 +0,0 @@
-from enum import Enum
-
-
-class AlbumVersionEnum(Enum):
-    """
-    Enum that registers supported album versions.
-    """
-
-    Explicit = ("explicit",)
-    _360_AUDIO = ("360 audio",)
-
-    ANNIVERSARY_EDITION = ("anniversary",)
-    DIAMOND_EDITION = ("diamond",)
-    Centennial_EDITION = ("centennial",)
-    GOLDEN_EDITION = ("gold",)
-    PLATINUM_EDITION = ("platinum",)
-    SILVER_EDITION = ("silver",)
-    ULTIMATE_EDITION = ("ultimate",)
-
-    EXPANDED = ("expanded",)
-    EXTENDED = ("extended",)
-
-    DELUXE = ("deluxe",)
-    SUPER_DELUXE = ("super deluxe",)
-    COMPLETE = ("complete",)
-
-    LEGACY_EDITION = ("legacy",)
-    SPECIAL_EDITION = ("special",)
-    COLLECTORS_EDITION = ("collector",)
-    ARCHIVE_EDITION = ("archive",)
-
-    Acoustic = ("acoustic",)
-    instrumental = ("instrumental",)
-    DOUBLE_DISC = ("double disc", "double disk")
-    Unplugged = ("unplugged",)
-
-    SUMMER_EDITION = ("summer",)
-    WINTER_EDITION = ("winter",)
-    SPRING_EDITION = ("spring",)
-    FALL_EDITION = ("fall",)
-
-    BONUS_EDITION = ("bonus",)
-    BONUS_TRACK = ("bonus track",)
-
-    ORIGINAL = ("original", " og ", "og ")
-    INTL_VERSION = ("international",)
-    UK_VERSION = ("uk version",)
-    US_VERSION = ("us version",)
-    PARENTAL_ADVISORY = ("PA version",)
-
-    Limited_EDITION = ("limited",)
-
-    MONO = ("mono",)
-    STEREO = ("stereo",)
-
-    HI_RES = ("Hi-Res",)
-    RE_MIX = ("re-mix",)
-    RE_RECORDED = ("re-recorded", "rerecorded")
-    REISSUE = ("reissue",)
-    REMASTERED = ("remaster",)
-
-
-def get_all_keywords():
-    """
-    Returns a joint string of all album versions.
-    """
-    return "|".join("|".join(i.value) for i in AlbumVersionEnum)