DBP-61: implement database structure retrieval

[pan93412]

• feat(sqlrunner): implement GetDatabaseStructure method
• feat(graph): implement Structure in Database type

[linear]

DBP-61 Implement database structure retrieval

[Copilot]

Pull Request Overview

This PR implements database structure retrieval functionality, adding the ability to get table and column information from database schemas. The implementation includes both backend SQL query capabilities and GraphQL API integration.

Key changes:

• Added GetDatabaseStructure method to SQLRunner for retrieving table and column metadata
• Integrated database structure retrieval into the GraphQL API through Database type extension
• Added comprehensive test coverage for various database structure scenarios

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
internal/sqlrunner/sqlrunner.go	Implements GetDatabaseStructure method using SQLite system tables
internal/sqlrunner/models.go	Defines DatabaseStructure and DatabaseTable data models
internal/sqlrunner/sqlrunner_test.go	Comprehensive tests for database structure retrieval functionality
graph/database.resolvers.go	GraphQL resolver for database structure field
graph/database.graphqls	GraphQL schema extension for database structure types
graph/model/models_gen.go	Generated GraphQL model types
graph/ent.resolvers.go	Updates resolver registration and formatting
graph/question.resolvers.go	Adds lastSubmission resolver and ordering to userSubmissions
graph/question.graphqls	GraphQL schema updates for question submissions
graph/user.resolvers.go	Generated code version update
graph/event.resolvers.go	Generated code version update

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