Missing author_association field in list_issues and pull request responses

首先阅读 pkg/github/issues.go 和 pkg/github/minimal_types.go，重点关注 IssueFragment、fragmentToMinimalIssue()、MinimalPullRequest 和 convertToMinimalPullRequest()。验证 list_issues 的 GraphQL 响应以及 list_pull_requests 和 pull_request_read 的 REST 响应；当每个响应都包含带有可用作者关联值的 author_association 时，工作即完成。

Summary

The author_association field is missing from several MCP response types, which prevents downstream consumers from determining author permissions (e.g., OWNER, MEMBER, COLLABORATOR, CONTRIBUTOR, NONE).

Affected Endpoints

1. list_issues (GraphQL path)

• IssueFragment struct does not request authorAssociation in the GraphQL query
• fragmentToMinimalIssue() does not populate AuthorAssociation in MinimalIssue
• Note: The REST path in convertToMinimalIssue() correctly sets AuthorAssociation: issue.GetAuthorAssociation()

2. list_pull_requests and pull_request_read (REST path)

• MinimalPullRequest struct is missing the author_association field entirely
• convertToMinimalPullRequest() does not set it
• The raw *github.PullRequest from the go-github library has AuthorAssociation available via pr.GetAuthorAssociation()

Already Working

• issue_read (single issue GET) — uses REST convertToMinimalIssue() which includes author_association ✅
• get_review_comments — MinimalPullRequestReview includes author_association ✅

Impact

Consumers that rely on author_association to determine author trust level (OWNER, MEMBER, COLLABORATOR, CONTRIBUTOR, NONE) cannot make correct decisions when this field is missing from list_issues and pull request responses.

For example, a repo admin's issues are incorrectly treated as untrusted because their author_association of "MEMBER" is not present in the response.

Suggested Fix

For list_issues (GraphQL):

1. Add AuthorAssociation githubv4.String to IssueFragment struct in issues.go
2. Set AuthorAssociation: string(fragment.AuthorAssociation) in fragmentToMinimalIssue() in minimal_types.go

For pull requests (REST):

1. Add AuthorAssociation string \x60json:"author_association,omitempty"\x60 to MinimalPullRequest struct in minimal_types.go
2. Set AuthorAssociation: pr.GetAuthorAssociation() in convertToMinimalPullRequest() in minimal_types.go

References

• pkg/github/issues.go — IssueFragment struct
• pkg/github/minimal_types.go — MinimalIssue, MinimalPullRequest, fragmentToMinimalIssue(), convertToMinimalPullRequest()