[backport] Bound ui_get pagination to prevent latency spikes (upstream main)

[gastrodon]

Summary

ui_get backs synchronous MCP App UI pickers (label/assignee/milestone/branch/reviewer dropdowns). Each method paginated GitHub API results in an unbounded loop (100 per page, looping until NextPage==0). On large repos/orgs this fans into dozens of sequential API calls — production telemetry showed tail latency spiking to ~20 minutes.

Fix: introduce uiGetMaxPages = 10 (1000 items maximum) constant in ui_tools.go. All pagination loops for labels, assignees, milestones, branches, and reviewers (collaborators + teams loops) now break at uiGetMaxPages. A has_more boolean is added to each response to signal truncation. uiGetIssueTypes and issue_fields are single-request and left unchanged.

Upstream reference

• version: upstream main (post v1.4.0, unreleased)
• commits: github@63d313a
• PR: fix(ui_get): bound pagination to cap latency github/github-mcp-server#2766

Fork conflict

None. The fork does not add MCP App UI tools.

Context

ui_get feeds type-ahead pickers that pair with user search input, so responsiveness matters more than completeness. Truncating at 1000 results with a has_more flag gives the UI a signal to show a "type to filter" hint rather than implying the list is exhaustive.

[gastrodon]

Unified Changelog — upstream main since v1.4.0

See #10 for the full changelog. Summary:

• [backport] OAuth 2.1 stdio login (upstream main) [story] #13 (story): OAuth 2.1 stdio login → sub-issues [backport] OAuth 2.1 core library — PKCE + device flows (upstream main) #10 [backport] Wire OAuth 2.1 login into stdio server (upstream main) #11 [backport] OAuth build-time credentials + docs (upstream main) #12
• [backport] Issue dependency read/write tools (upstream main) #14: Issue dependency read/write tools
• [backport] get_parent method for issue_read (upstream main) #15: get_parent for issue_read
• [backport] Promote issue fields to default, remove legacy issue_write methods (upstream main) #16: Promote issue fields, remove legacy issue_write
• [backport] Remove show_ui parameter, centralize show/defer decision (upstream main) #17: Remove show_ui, centralize show/defer
• [backport] Fix delete:true on issue fields — REST DELETE fallback (upstream main) #18: Fix delete:true on issue fields
• [backport] Bound ui_get pagination to prevent latency spikes (upstream main) #19: Bound ui_get pagination
• [backport] Fix issue_write MCP App form gating for labels/assignees/milestone/type (upstream main) #20: Fix issue_write form gating
• [backport] Validate required params in add_comment_to_pending_review (upstream main) #21: Validate required params in add_comment_to_pending_review

[gastrodon]

No-op. The fork already has uiGetMaxPages = 10 constant in pkg/github/ui_tools.go (line 30), with bounded pagination and has_more flag in all ui_get loops. No work needed.