Weekly submission status/statistics bug fix — fetchActiveProblemIds CLOSED exclusion

Background

Users reported that the weekly submission statistics page showed incorrect counts — problems marked as CLOSED were not appearing in the statistics, even though submissions had been made for them. Root cause: fetchActiveProblemIds() in the Submission service was filtering only ACTIVE problems, silently dropping CLOSED ones.

Goals

1. Fix fetchActiveProblemIds() to include CLOSED problems in weekly statistics
2. Add regression tests to prevent recurrence
3. Verify no impact on other submission flows

Work Summary

Root Cause

// Before (bug): only ACTIVE problems returned
async fetchActiveProblemIds(): Promise<string[]> {
  const problems = await this.problemRepo.find({
    where: { status: ProblemStatus.ACTIVE },
  });
  return problems.map(p => p.id);
}

// After (fix): ACTIVE + CLOSED both included
async fetchActiveProblemIds(): Promise<string[]> {
  const problems = await this.problemRepo.find({
    where: [
      { status: ProblemStatus.ACTIVE },
      { status: ProblemStatus.CLOSED },
    ],
  });
  return problems.map(p => p.id);
}

The function name fetchActiveProblemIds was intentionally kept for backward compatibility (renaming would require updates across multiple callers). A JSDoc comment was added clarifying it includes CLOSED problems.

Verification

Decisions

• Include CLOSED in statistics: CLOSED problems should appear in weekly statistics because submissions were made during their active period. Excluding them produces an incomplete view.
• Keep function name: fetchActiveProblemIds name retained to minimize diff size and caller updates. JSDoc clarification is sufficient.
• TypeORM where array for OR: TypeORM's array syntax in where produces WHERE status = 'ACTIVE' OR status = 'CLOSED' — no raw query needed.