feat: add vmux setup and vmux hook for Claude Code integration

- vmux setup: idempotently adds hooks to ~/.claude/settings.json
- vmux hook: receives Claude Code hook events via env vars and forwards to daemon
- Daemon handles "hook" action on Unix socket (no HTTP server needed)
- Hooks provide instant state detection (permission/question/idle)

setup.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// parseHookEnv builds a HookEvent from Claude Code hook environment variables.
+func parseHookEnv() HookEvent {
+	return HookEvent{
+		SessionID:        os.Getenv("SESSION_ID"),
+		Cwd:              os.Getenv("SESSION_CWD"),
+		HookEventName:    os.Getenv("HOOK_EVENT_NAME"),
+		NotificationType: os.Getenv("NOTIFICATION_TYPE"),
+		ToolName:         os.Getenv("TOOL_NAME"),
+	}
+}
+
+// runSetup adds vmux hooks to ~/.claude/settings.json (idempotent).
+func runSetup() {
+	home := os.Getenv("HOME")
+	settingsPath := filepath.Join(home, ".claude", "settings.json")
+
+	vmuxBin, err := os.Executable()
+	if err != nil {
+		vmuxBin = filepath.Join(home, "Code", "vibe", "vmux", "vmux")
+	}
+
+	data, err := os.ReadFile(settingsPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Cannot read %s: %v\n", settingsPath, err)
+		os.Exit(1)
+	}
+
+	var settings map[string]interface{}
+	if err := json.Unmarshal(data, &settings); err != nil {
+		fmt.Fprintf(os.Stderr, "Cannot parse %s: %v\n", settingsPath, err)
+		os.Exit(1)
+	}
+
+	hooks, _ := settings["hooks"].(map[string]interface{})
+	if hooks == nil {
+		hooks = make(map[string]interface{})
+		settings["hooks"] = hooks
+	}
+
+	hookCommand := vmuxBin + " hook"
+	vmuxHook := map[string]interface{}{
+		"type":    "command",
+		"command": hookCommand,
+		"timeout": 5,
+	}
+
+	events := []string{"Notification", "Stop", "PostToolUse", "PreToolUse"}
+	changed := false
+
+	for _, event := range events {
+		entries, _ := hooks[event].([]interface{})
+
+		if hasVmuxHook(entries, hookCommand) {
+			continue
+		}
+
+		entry := map[string]interface{}{
+			"hooks": []interface{}{vmuxHook},
+		}
+
+		hooks[event] = append(entries, entry)
+		changed = true
+	}
+
+	if !changed {
+		fmt.Println("vmux hooks already configured.")
+		return
+	}
+
+	out, err := json.MarshalIndent(settings, "", "    ")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Cannot marshal settings: %v\n", err)
+		os.Exit(1)
+	}
+
+	if err := os.WriteFile(settingsPath, out, 0o644); err != nil {
+		fmt.Fprintf(os.Stderr, "Cannot write %s: %v\n", settingsPath, err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("vmux hooks added to %s for events: %v\n", settingsPath, events)
+	fmt.Println("Restart Claude Code sessions for hooks to take effect.")
+}
+
+func hasVmuxHook(entries []interface{}, hookCommand string) bool {
+	for _, entry := range entries {
+		e, _ := entry.(map[string]interface{})
+		hookList, _ := e["hooks"].([]interface{})
+		for _, h := range hookList {
+			hm, _ := h.(map[string]interface{})
+			if cmd, _ := hm["command"].(string); cmd == hookCommand {
+				return true
+			}
+		}
+	}
+	return false
+}