Add notification hook with macOS speech synthesis

- Speaks Claude notifications using the 'say' command
- Handles both permission requests and regular notifications
- Only runs on macOS systems
- Non-blocking execution to avoid delays

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

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

internal/handlers/notification.go

@@ -0,0 +1,72 @@
+package handlers
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"os/exec"
+	"runtime"
+	"strings"
+
+	"github.com/imjasonh/hooks/internal/hooks"
+)
+
+func init() {
+	hooks.RegisterHook(hooks.EventNotification, "*", SpeakNotification)
+}
+
+func SpeakNotification(ctx context.Context, input hooks.HookInput) (hooks.HookOutput, error) {
+	// Only run on macOS
+	if runtime.GOOS != "darwin" {
+		return hooks.HookOutput{Decision: "continue"}, nil
+	}
+
+	// Check if say command is available
+	if _, err := exec.LookPath("say"); err != nil {
+		slog.Debug("say command not found", "error", err)
+		return hooks.HookOutput{Decision: "continue"}, nil
+	}
+
+	// Build the message to speak
+	var message string
+	if input.Notification.Permission != "" {
+		// Permission request
+		message = fmt.Sprintf("Claude is requesting permission to use %s. %s", 
+			input.Notification.Tool, 
+			input.Notification.Message)
+	} else {
+		// Regular notification
+		message = fmt.Sprintf("Notification from %s: %s",
+			input.Notification.Tool,
+			input.Notification.Message)
+	}
+
+	// Sanitize the message for speech
+	message = strings.ReplaceAll(message, "\n", " ")
+	message = strings.ReplaceAll(message, "\"", "'")
+
+	// Run say command with a shorter message if it's too long
+	if len(message) > 200 {
+		message = message[:197] + "..."
+	}
+
+	cmd := exec.CommandContext(ctx, "say", "-v", "Samantha", message)
+	if err := cmd.Start(); err != nil {
+		slog.Error("failed to start say command", "error", err)
+		return hooks.HookOutput{Decision: "continue"}, nil
+	}
+
+	// Don't wait for completion to avoid blocking
+	go func() {
+		if err := cmd.Wait(); err != nil {
+			slog.Debug("say command failed", "error", err)
+		}
+	}()
+
+	slog.Info("speaking notification",
+		"tool", input.Notification.Tool,
+		"permission", input.Notification.Permission != "",
+		"message_length", len(message))
+
+	return hooks.HookOutput{Decision: "continue"}, nil
+}