storkit: merge 389_story_whatsapp_phone_number_allowlist_authorization

.storkit/bot.toml.whatsapp-twilio.example

@@ -22,3 +22,8 @@ twilio_whatsapp_number = "+14155238886"
 
 # Maximum conversation turns to remember per user (default: 20).
 # history_size = 20
+
+# Optional: restrict which phone numbers can interact with the bot.
+# When set, only listed numbers are processed; all others are silently ignored.
+# When absent or empty, all numbers are allowed (open by default).
+# whatsapp_allowed_phones = ["+15551234567", "+15559876543"]