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

pyproject.toml

@@ -1,74 +0,0 @@
-[build-system]
-requires = ["setuptools", "setuptools-scm"]
-build-backend = "setuptools.build_meta"
-
-[project]
-name = "swingmusic"
-description = "Swing Music"
-readme = "README.md"
-requires-python = ">=3.11"
-dynamic = ["version"]
-
-dependencies = [
-    "pillow>=11.1.0",
-    "Flask>=3.1.0",
-    "Flask-Cors>=3.0.10",
-    "requests>=2.27.1",
-    "colorgram.py>=1.2.0",
-    "tqdm>=4.65.0",
-    "tinytag>=2.1.1",
-    "Unidecode>=1.3.6",
-    "psutil>=5.9.4",
-    "show-in-file-manager>=1.1.4",
-    "flask-compress>=1.13",
-    "tabulate>=0.9.0",
-    "setproctitle>=1.3.2",
-    "locust>=2.20.1",
-    "watchdog>=4.0.0",
-    "flask-jwt-extended>=4.6.0",
-    "sqlalchemy>=2.0.31",
-    "memory-profiler>=0.61.0",
-    "sortedcontainers>=2.4.0",
-    "xxhash>=3.4.1",
-    "ffmpeg-python>=0.2.0",
-    "schedule>=1.2.2",
-    "pillow>=11.1.0",
-    "flask-openapi3==3.0.2",
-    "rapidfuzz==3.11.0",
-    "pendulum>=3.0.0",
-    "pystray>=0.19.5",
-    "waitress>=3.0.2; sys_platform == 'win32'",
-    "bjoern >=3.2.2; sys_platform != 'win32'",
-]
-
-[project.optional-dependencies]
-build = [
-    "pyinstaller"
-]
-
-[tool.uv]
-dependency-metadata = [
-    { name = "waitress", version = "3.0.2", requires-dist = [], requires-python = ">=3.11" },
-    { name = "bjoern", version="3.2.2", requires-dist = [], requires-python = ">=3.11"}
-]
-
-[project.scripts]
-swingmusic = "swingmusic.__main__:run"
-
-
-[project.urls]
-Homepage = "https://swingmx.com/"
-Repository = "https://github.com/swingmx/swingmusic"
-Documentation = "https://swingmx.com/guide/introduction.html"
-Issues = "https://github.com/swingmx/swingmusic/issues"
-
-
-[tool.setuptools_scm]
-version_scheme = "only-version"
-local_scheme = "no-local-version"
-fallback_version = "v0.0.0"
-
-[dependency-groups]
-dev = [
-    "twine>=6.1.0",
-]