[TODO Import][Server][Backlog] Problem contribution pipeline completion

[ferneediaz]

Imported from server/TODO.md.

Kanban

• Column: Backlog
• Area: Server

📋 TODO - Problem Contribution Pipeline (LOW PRIORITY)

Import community-contributed problems from the repo.

Task Breakdown:

1. Problem Format in Repo

problems/
  two-sum/
    description.md       # Title, description, constraints, hints, complexity
    testcases.json       # Array of { input, expectedOutput, isHidden }
    starter-code/
      javascript.js
      python.py
      typescript.ts
      java.java
      cpp.cpp
      c.c
      rust.rs
    solution/
      editorial.md       # Solution explanation
      solution.py        # Reference solution

2. Import Script

• Create scripts/import-problems.ts — CLI script to import from problems/ directory
• Parse description.md frontmatter (title, difficulty, tags, constraints, complexity)
• Import test cases from testcases.json
• Import starter code from starter-code/ directory
• Upsert logic (update if problem with same slug exists)
• Dry-run mode (show what would be imported)
• Success Criteria: Script imports problems into DB ✅

3. Validation

• Validate test cases have input + expectedOutput
• Validate at least 1 starter code file exists
• Validate description.md has required frontmatter fields
• Run reference solution against test cases to verify correctness
• Success Criteria: Invalid problems rejected with clear errors ✅

4. Admin Review Integration

• GET /api/problems/pending — List problems in DRAFT status (admin only)
• POST /api/problems/:id/approve — Approve problem (move to ACTIVE)
• POST /api/problems/:id/reject — Reject problem with reason
• Add status field to Problem model (DRAFT, ACTIVE, REJECTED)
• Success Criteria: Review workflow works ✅

5. Tests

• Import script tests (valid problem, invalid problem, upsert)
• Review workflow tests
• Success Criteria: All import tests passing ✅

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