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/specs/service-knowledge-base/spec.md

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+## ADDED Requirements
+
+### Requirement: Knowledge base stores service information
+The system SHALL maintain a knowledge base containing playgroup service information including fees, regulations, opening hours, policies, and frequently asked questions.
+
+#### Scenario: Knowledge base content categories
+- **WHEN** the knowledge base is queried
+- **THEN** it SHALL be able to provide information about fees, regulations, opening hours, policies, and FAQs
+
+### Requirement: Agent accesses knowledge base to answer questions
+The system SHALL enable the AI agent to query the knowledge base and provide accurate answers to parent questions.
+
+#### Scenario: Parent asks about fees
+- **WHEN** a parent asks about service fees or pricing
+- **THEN** the agent SHALL retrieve current fee information from the knowledge base and respond accurately
+
+#### Scenario: Parent asks about regulations
+- **WHEN** a parent asks about playgroup rules or regulations
+- **THEN** the agent SHALL retrieve the relevant policies and explain them clearly
+
+#### Scenario: Unknown question
+- **WHEN** a parent asks a question not covered in the knowledge base
+- **THEN** the agent SHALL indicate it cannot answer and suggest contacting the admin directly
+
+### Requirement: Knowledge base is admin-maintainable
+The system SHALL allow the admin to update knowledge base content without requiring technical skills or code changes.
+
+#### Scenario: Admin updates fee information
+- **WHEN** the admin edits the fee information in the knowledge base
+- **THEN** the agent SHALL use the updated information in subsequent responses
+
+#### Scenario: Admin adds new FAQ entry
+- **WHEN** the admin adds a new FAQ entry to the knowledge base
+- **THEN** the agent SHALL be able to answer questions related to that entry
+
+### Requirement: Knowledge base uses simple editable format
+The system SHALL store knowledge base content in a human-readable format (e.g., markdown or structured text files).
+
+#### Scenario: Knowledge base file format
+- **WHEN** the admin views the knowledge base files
+- **THEN** the content SHALL be readable and editable without specialized tools