Day 3: Seed Number Properties topic (+3 lessons, +6 questions)

[DMDaudio]

What does this PR add or change?

Adds full content coverage of the Quant number-properties topic — the last Foundations topic in curriculum.md that had no lessons at all (previously just one question).

• 3 lessons (one per subtopic):
  • factors-multiples — Factors, Multiples, Primes & Divisibility (prime factorization, divisor counting, GCD/LCM, perfect squares, divisibility rules).
  • odds-evens-signs — Odds, Evens & Sign Rules (parity of sums/products, sign rules, consecutive integers, "must be true" strategy).
  • remainders — Remainders & Modular Thinking (division form, scaling/adding remainders, simultaneous conditions).
• 6 questions (0017–0022), two per subtopic, spanning medium and hard:
  • factors-multiples-0017 (LCM, medium), factors-multiples-0018 (perfect-square multiplier, hard)
  • odds-evens-signs-0019 (parity must-be-true, medium), odds-evens-signs-0020 (sign chaining, medium)
  • remainders-0021 (scaling a remainder, medium), remainders-0022 (two simultaneous moduli, hard)

Rebuilt docs/data/content.json via node scripts/build.mjs — now 38 questions, 11 lessons, no validator warnings.

Type of change

• New question(s)
• New lesson(s)
• Fix to existing content (answer / explanation / tag)
• Tooling / docs / schema

Author checklist

• This is my own original work — not copied or paraphrased from any real GMAT question or prep material.
• Front-matter follows CONTENT_SCHEMA.md (id matches the filename; topic/subtopic exist in curriculum.md).
• I solved every question myself and confirmed exactly one answer choice is correct.
• Each explanation would help someone who got the question wrong, and names the trap where relevant.
• status is in-review. I did not set my own content to verified.

For reviewers

• I solved the question(s) without reading the keyed answer first and got the same answer.
• Exactly one choice is correct; distractors are plausible.
• Explanation and tags (section / topic / difficulty) are accurate.
• If approving: bumped status to verified and added my handle to reviewers.

🤖 Generated with Claude Code

https://claude.ai/code/session_019vb2R14JLMiDc788ZZfc3W

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