feat(graph): implement statistics of questions

[pan93412]

No description provided.

[linear]

DBP-102 API 可以回傳一個題目的嘗試次數和攻克次數

[Copilot]

Pull Request Overview

This PR implements statistics tracking for questions, providing metrics on submission counts, success rates, and user engagement. The feature enables GraphQL queries to retrieve aggregated data about question performance.

Key changes:

• Added QuestionStatistics model with fields for tracking correct submissions, total submissions, attempted users, and passed users
• Implemented GraphQL resolver to compute statistics by querying the submission database
• Added comprehensive test coverage for various submission scenarios including edge cases

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
models/question.go	Defines the QuestionStatistics struct with fields for submission and user metrics
graph/question.resolvers.go	Implements the Statistics resolver that queries and aggregates submission data
graph/question.graphqls	Extends the Question type with a statistics field and defines the QuestionStatistics GraphQL type
graph/question_resolver_test.go	Adds comprehensive test cases covering different submission scenarios, authorization, and edge cases

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