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/data/__init__.py

@@ -0,0 +1,81 @@
+ARTIST_SPLIT_IGNORE_LIST = {
+    "AC/DC",
+    "Sonny & Cher",
+    "Bob marley & the wailers",
+    "Crosby, Stills, Nash & Young",
+    "Booker T. & the M.G.'s",
+    "Maurice Williams & The Zodiacs",
+    "Frank DeVol and His Orchestra",
+    "Tommy James & the Shondells",
+    "Smith & Thell",
+    "Peter, Paul & Mary",
+    "Simon & Garfunkel",
+    "Judy & Mary",
+    "Florence & The Machine",
+    "Belle & Sebastian",
+    "C&C Music Factory",
+    "C & C Music Factory",
+    "FO&O",
+    "The Product G&B",
+    "Big Brother and the Holding Company",
+    "Tyler, The Creator",
+    "Eric B. & Rakim",
+    "DJ Jazzy Jeff & The Fresh Prince",
+    "Rob Base & DJ E-Z Rock",
+    "Nick Cave & the Bad Seeds",
+    "For King + Country",
+    "For King & Country",
+    "Robson & Jerome",
+    "Charles & Eddie",
+    "Womack & Womack",
+    "Pepsi & Shirlie",
+    "Mel & Kim",
+    "Wendy & Lisa",
+    "Tony! Toni! Toné!",
+    "Phillips, Craig & Dean",
+    "Crosby & Nash",
+    "Blood, Sweat & Tears",
+    "Mike + The Mechanics",
+    "Earth, Wind & Fire",
+    "Emerson, Lake & Palmer",
+    "Mumford & Sons",
+    "Hall & Oates",
+    "Tom Petty & The Heartbreakers",
+    "Sly & the Family Stone",
+    "Booker T. & the M.G.'s",
+    "KC & the Sunshine Band",
+    "Huey Lewis & the News",
+    "Joan Jett & the Blackhearts",
+    "Echo & the Bunnymen",
+    "Katrina & the Waves",
+    "Gladys Knight & the Pips",
+    "Martha & the Vandellas",
+    "Martha Reeves and the Vandellas",
+    "? and the Mysterians",
+    "Kool & the Gang",
+    "Josie & the Pussycats",
+    "Dan + Shay",
+    "Brooks & Dunn",
+    "Peaches & Herb",
+    "Seals & Crofts",
+    "Loggins & Messina",
+    "England Dan & John Ford Coley",
+    "Ashford & Simpson",
+    "Sam & Dave",
+    "Ike & Tina Turner",
+    "Sonny & Cher",
+    "Captain & Tennille",
+    "Hootie & the Blowfish",
+    "Diana Ross & the Supremes",
+    "Herb Alpert & the Tijuana Brass",
+    "The Mamas & the Papas",
+    "Gerry & the Pacemakers",
+    "Chloe x Halle",
+    "Durand Jones & The Indications",
+    "St. Paul & The Broken Bones",
+    "Nathaniel Rateliff & The Night Sweats",
+    "Aly & AJ",
+    "Maddie & Tae",
+    "Nico & Vinz",
+    "Yusuf / Cat Stevens"
+}