fix: remove node_modules

README.md

@@ -51,4 +51,53 @@ spore-ui/
 - **Backend**: Express.js, Node.js
 - **Frontend**: Vanilla JavaScript, CSS3, HTML5
 - **API**: SPORE Embedded System API
-- **Design**: Glassmorphism, CSS Grid, Flexbox
+- **Design**: Glassmorphism, CSS Grid, Flexbox
+
+## TODO
+
+## UDP Auto Discovery
+
+The backend now includes automatic UDP discovery for SPORE nodes on the network. This eliminates the need for hardcoded IP addresses.
+
+### How It Works
+
+1. **UDP Server**: The backend listens on port 4210 for UDP messages
+2. **Discovery Message**: Nodes send `CLUSTER_DISCOVERY` messages to broadcast address `255.255.255.255:4210`
+3. **Auto Configuration**: When a discovery message is received, the source IP is automatically used to configure the SporeApiClient
+4. **Dynamic Updates**: The system automatically switches to the most recently seen node as the primary connection
+
+### Discovery Endpoints
+
+- `GET /api/discovery/nodes` - View all discovered nodes and current status
+- `POST /api/discovery/refresh` - Manually trigger discovery refresh
+- `POST /api/discovery/primary/:ip` - Manually set a specific node as primary
+- `GET /api/health` - Health check including discovery status
+
+### Testing Discovery
+
+Use the included test script to send discovery messages:
+
+```bash
+# Send to broadcast address
+npm run test-discovery broadcast
+
+# Send to specific IP
+npm run test-discovery 192.168.1.100
+
+# Send multiple messages
+npm run test-discovery broadcast 5
+```
+
+### Node Behavior
+
+- Nodes should send `CLUSTER_DISCOVERY` messages periodically (recommended: every 30-60 seconds)
+- The backend automatically cleans up stale nodes (not seen for 5+ minutes)
+- The most recently seen node becomes the primary connection
+- All API endpoints automatically use the discovered node IPs
+
+### Configuration
+
+- UDP Discovery Port: 4210 (configurable via `UDP_PORT` constant)
+- Discovery Message: `CLUSTER_DISCOVERY` (configurable via `DISCOVERY_MESSAGE` constant)
+- Stale Node Timeout: 5 minutes (configurable in `cleanupStaleNodes()` function)
+- Health Check Interval: 5 seconds (configurable in `setInterval`)