Replace --broadcast flag with per-universe target config

- Remove --broadcast CLI flag
- Add [[target]] config section for per-universe destination addresses
- Each ArtNet output universe can have its own target IP (broadcast or unicast)
- ArtPoll discovery broadcasts to all unique target addresses
- Falls back to configured target when no nodes discovered for universe

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

config/config.go

@@ -11,9 +11,41 @@ import (
 
 // Config represents the application configuration
 type Config struct {
+	Targets  []Target  `toml:"target"`
 	Mappings []Mapping `toml:"mapping"`
 }
 
+// Target represents a target address for an output universe
+type Target struct {
+	Universe TargetUniverse `toml:"universe"`
+	Address  string         `toml:"address"`
+}
+
+// TargetUniverse is a universe that can be parsed from string or int
+type TargetUniverse struct {
+	artnet.Universe
+}
+
+func (t *TargetUniverse) UnmarshalTOML(data interface{}) error {
+	switch v := data.(type) {
+	case string:
+		u, err := parseUniverse(v)
+		if err != nil {
+			return err
+		}
+		t.Universe = u
+		return nil
+	case int64:
+		t.Universe = artnet.Universe(v)
+		return nil
+	case float64:
+		t.Universe = artnet.Universe(int64(v))
+		return nil
+	default:
+		return fmt.Errorf("unsupported universe type: %T", data)
+	}
+}
+
 // Protocol specifies the output protocol
 type Protocol string
 
@@ -211,6 +243,13 @@ func Load(path string) (*Config, error) {
 		return nil, fmt.Errorf("failed to load config: %w", err)
 	}
 
+	// Validate targets
+	for i, t := range cfg.Targets {
+		if t.Address == "" {
+			return nil, fmt.Errorf("target %d: address is required", i)
+		}
+	}
+
 	for i := range cfg.Mappings {
 		m := &cfg.Mappings[i]
 		if m.From.ChannelStart < 1 || m.From.ChannelStart > 512 {
@@ -286,3 +325,12 @@ func (c *Config) SACNSourceUniverses() []uint16 {
 	}
 	return result
 }
+
+// TargetMap returns a map of universe to target address
+func (c *Config) TargetMap() map[artnet.Universe]string {
+	result := make(map[artnet.Universe]string)
+	for _, t := range c.Targets {
+		result[t.Universe.Universe] = t.Address
+	}
+	return result
+}