feat(catalog): add get_issue_user_reports tool

[Pragyan14]

What

Exposes GET /api/0/issues/{issue_id}/user-reports/ through the MCP catalog as a new get_issue_user_reports tool.

Changes

• schema.ts — adds UserReportSchema and UserReportListSchema matching the real API response shape
• client.ts — adds getIssueUserReports() method using the org-scoped endpoint /organizations/{org}/issues/{id}/user-reports/
• types.ts — adds UserReportList type inferred from the list schema
• tools/catalog/get-issue-user-reports.ts — new catalog tool following existing patterns (get-issue-activity, get-issue-tag-values)
• tools/catalog/index.ts — registers the new tool
• mcp-server-mocks — adds mock handler + issue-user-reports.json fixture based on real API response

Testing

• Reproduced the gap against a real sentry.io project: confirmed GET /issues/{id}/user-reports/ returns feedback data that was completely invisible to agents before this change
• Confirmed org-scoped URL (/organizations/{org}/issues/{id}/user-reports/) returns identical data
• Unit test passes with snapshot matching real formatted output
• tsc and lint pass clean on @sentry/mcp-core
• Tool shows as accessible in catalog summary (43 tools, 0 orphaned)

Notes

• Tool is exposed via catalog only (behind search_sentry_tools / execute_sentry_tool), per maintainer guidance
• One pre-existing test failure in @sentry/mcp-agent-cli-test (setup.test.ts) is a Windows path normalization bug unrelated to this change — confirmed by reproducing with a clean stash

[dcramer]

cleaning up a couploe things. one thing i generally do is point the agent at current sentry to make sure theres no gaps in schemas, but broadly speaking patch is good and we'll get it landed today, ty!