🐛 fix: harden connection lifecycle and add session safeguards

src/config.go

@@ -28,6 +28,8 @@ type Config struct {
 	MaxAuthAttempts     int
 	HandshakeTimeout    time.Duration
 	MaxDimension        int
+	MaxTerminalCells    int
+	SessionTimeout      time.Duration
 	RenderCacheMB       int
 	BrightnessThreshold int
 	Charset             string
@@ -126,6 +128,8 @@ func loadConfig() Config {
 		MaxAuthAttempts:     envInt("MAX_AUTH_ATTEMPTS", 6, 1, maxInt),
 		HandshakeTimeout:    envDurationMs("HANDSHAKE_TIMEOUT", 10*time.Second),
 		MaxDimension:        envInt("MAX_DIMENSION", 512, 1, 4096),
+		MaxTerminalCells:    envInt("MAX_TERMINAL_CELLS", 500*512, 1, maxInt),
+		SessionTimeout:      envDurationMs("SESSION_TIMEOUT", 10*time.Minute),
 		RenderCacheMB:       envInt("RENDER_CACHE_MB", 256, 0, maxInt),
 		BrightnessThreshold: envInt("BRIGHTNESS_THRESHOLD", 40, 0, 100),
 		Charset:             envString("CHARSET", "detailed"),