Add project scope documentation for AI playgroup registration system

Define complete non-technical scope for replacing Google Forms registration
with an AI-powered conversational agent. Includes:

- Registration data requirements (13 fields with validation rules)
- Knowledge base content (fees, regulations, schedule, FAQ from official PDFs)
- Conversation flow design with bilingual support (German/English)
- Agent personality guidelines (warm & friendly tone)
- Admin notification routing by playgroup type
- Email reminder system for incomplete registrations
- Data export formats (CSV/JSON)
- Channel configuration (email + chat)
- Release priorities (MVP scope defined)

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

openspec/changes/define-project-scope/content/knowledge-base/README.md

@@ -0,0 +1,25 @@
+# Knowledge Base
+
+This directory contains the information the AI agent uses to answer parent questions about the playgroup service.
+
+## Files
+
+| File | Content |
+|------|---------|
+| `fees.md` | Pricing, payment terms, discounts |
+| `schedule.md` | Opening hours, locations, contacts |
+| `regulations.md` | Policies, rules, requirements |
+| `faq.md` | Frequently asked questions |
+
+## Maintenance
+
+To update information the agent provides:
+1. Edit the relevant markdown file
+2. Changes take effect immediately (no code deployment needed)
+
+## Format Guidelines
+
+- Use clear headings and sections
+- Keep answers concise but complete
+- Use tables for structured data (fees, schedules)
+- Mark placeholders with `*[To be completed]*`