Clean up and optimize codebase for production readiness

Performance & Reliability Improvements:
- Increase WebSocket buffer sizes from 1KB to 8KB for better throughput
- Increase broadcast channel buffer from 100 to 1000 messages
- Increase Beast message channel buffer from 1000 to 5000 messages
- Increase connection timeout from 10s to 30s for remote receivers

Code Quality Improvements:
- Remove debug output from production code (CPR Debug, Merger Update spam)
- Add MaxDistance constant to replace magic number (999999)
- Clean up comments for better maintainability
- Implement auto-enable for selected aircraft trails

Benefits:
- Much cleaner server logs without debug spam
- Better performance under high aircraft density
- More reliable WebSocket connections with larger buffers
- Improved fault tolerance with increased timeouts

🤖 Generated with [Claude Code](https://claude.ai/code)

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

internal/client/beast.go

@@ -73,7 +73,7 @@ func NewBeastClient(source *merger.Source, merger *merger.Merger) *BeastClient {
 		source:         source,
 		merger:         merger,
 		decoder:        modes.NewDecoder(source.Latitude, source.Longitude),
-		msgChan:        make(chan *beast.Message, 1000),
+		msgChan:        make(chan *beast.Message, 5000),
 		errChan:        make(chan error, 10),
 		stopChan:       make(chan struct{}),
 		reconnectDelay: 5 * time.Second,
@@ -146,7 +146,7 @@ func (c *BeastClient) run(ctx context.Context) {
 		addr := fmt.Sprintf("%s:%d", c.source.Host, c.source.Port)
 		fmt.Printf("Connecting to Beast stream at %s (%s)...\n", addr, c.source.Name)
 
-		conn, err := net.DialTimeout("tcp", addr, 10*time.Second)
+		conn, err := net.DialTimeout("tcp", addr, 30*time.Second)
 		if err != nil {
 			fmt.Printf("Failed to connect to %s: %v\n", c.source.Name, err)
 			c.source.Active = false