Update README: NASA Blue Marble texture + sprite particles docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -22,13 +22,15 @@ gaming-hub/
 │               └── index.ts    # Sounds, Upload, Normalisierung
 │
 ├── web/                    # Frontend (React 19 + Vite + TypeScript)
+│   ├── public/
+│   │   └── nasa-blue-marble.jpg  # NASA Blue Marble Globus-Textur (~28 MB)
 │   └── src/
 │       ├── App.tsx             # Root, Tab-Navigation, SSE-Handler
 │       ├── styles.css          # Globale Styles + Radio-Styles
 │       └── plugins/
 │           ├── radio/
-│           │   ├── RadioTab.tsx           # 3D Globe UI
-│           │   └── TileTextureManager.ts  # Tile Loader + Mercator-Reprojection
+│           │   ├── RadioTab.tsx           # 3D Globe UI (Sprite Particles)
+│           │   └── TileTextureManager.ts  # Tile Loader (Fallback)
 │           └── soundboard/
 │               ├── SoundboardTab.tsx      # Sound Grid UI
 │               └── soundboard.css         # Soundboard Styles
@@ -55,8 +57,9 @@ gaming-hub/
 
 ### Radio (`radio`)
 - 3D-Globus mit 30.000+ Radiosendern weltweit (Radio Garden API)
-- Tile-basierte Satellitentextur (Mercator -> Equirectangular Reprojection)
-- Server-seitiger Tile-Proxy mit In-Memory Cache (CDN erfordert Referer)
+- NASA Blue Marble Globus-Textur (statisches Satellitenbild)
+- Sender als Sprite-Partikel mit radialer Gradient-Textur (Theme-Farbe)
+- Server-seitiger Tile-Proxy mit In-Memory Cache (Fallback fuer CDN)
 - FFmpeg PCM-Streaming in Discord Voice Channels
 - Per-Guild Lautstaerke, Favoriten, Suche
 - Voice Stats (Ping, Status, Uptime) via SSE
@@ -259,7 +262,7 @@ NODE_ENV=production node dist/index.js
 | GET | `/api/radio/favorites` | Favoriten lesen |
 | POST | `/api/radio/favorites` | Favorit togglen |
 | GET | `/api/radio/status` | Aktueller Wiedergabestatus |
-| GET | `/api/radio/tile/:z/:x/:y` | Tile-Proxy (Satellitenbild) |
+| GET | `/api/radio/tile/:z/:x/:y` | Tile-Proxy (Fallback Satellitenbild) |
 
 ### Soundboard Plugin