feat: implement comprehensive GraphQL read interface (issue #9)

Adds a complete GraphQL API for querying MarkiTect database content including:

CORE FEATURES:
- Type-safe GraphQL schema with comprehensive field definitions
- Full database access: markdown files, schemas, ASTs, and metadata
- Advanced search capabilities with relevance scoring
- Pagination support for efficient data access
- Real-time schema introspection and development tools

IMPLEMENTATION:
- GraphQL schema definition with 6 core types (MarkdownFile, Schema, AST, etc.)
- Complete resolver implementation with database integration
- Flask-based GraphQL server with CORS support
- GraphQL Playground for interactive development
- Health check and schema introspection endpoints

CLI INTEGRATION:
- graphql-serve: Start GraphQL server with customizable options
- graphql-query: Execute queries from command line (local/remote)
- graphql-schema: Retrieve schema definition in SDL/JSON format
- graphql-examples: Comprehensive usage examples and documentation

API FEATURES:
- Single item queries (by ID or filename)
- List queries with filtering and pagination
- Full-text search across files and schemas
- Database statistics and analytics
- AST querying with JSONPath expressions
- Computed fields (word count, line count, etc.)

TESTING:
- Comprehensive test suite with 38 passing tests
- Unit tests for schema, resolvers, server, and client
- Integration tests for query execution
- Error handling and edge case coverage
- Mock and fixture support for isolated testing

DOCUMENTATION:
- Complete API documentation with examples
- Usage guide for all CLI commands
- Programming examples in Python and JavaScript
- Performance optimization guidelines
- Troubleshooting and security considerations

The GraphQL interface enables developers to build rich applications on top of
MarkiTect data with flexible, efficient querying capabilities.

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

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

markitect/graphql/__init__.py

@@ -0,0 +1,12 @@
+"""
+GraphQL interface for MarkiTect - Issue #9
+
+This package provides a GraphQL read interface for querying MarkiTect's
+database content including Markdown files, ASTs, and schemas.
+"""
+
+from .schema import schema
+from .server import GraphQLServer
+from .resolvers import Query
+
+__all__ = ['schema', 'GraphQLServer', 'Query']