[#13] Site comparison validation

[javaisbetterthanpython]

Summary

• Add docs/VALIDATION.md with a side-by-side checklist comparing jumbleddoubles.com vs this enhanced clone
• Document implemented upstream parity flows and fork-only features (fixed pairs, diversity scheduling)
• Include sample manual sessions for fixed pairs and back-to-back avoidance, intentional UI differences, and automated test mapping

Test plan

• yarn test:ci passes (21 tests)
• yarn build passes
• yarn lint passes (pre-existing hook warnings only)
• Full manual walkthrough using docs/VALIDATION.md checklist

Closes #13

Made with Cursor

[javaisbetterthanpython]

APPROVE

Docs-only PR that delivers docs/VALIDATION.md for issue #13. Scope is correct: single new file, no code changes.

Acceptance criteria

Criterion	Status
docs/VALIDATION.md checklist comparing original vs enhanced	Met — sections A–H with upstream/enhanced columns, sample sessions, and sign-off table
Upstream flows (landing, new game, rounds, edit players/courts/sit-outs, resume)	Met — covered in sections A–E with file references
New flows (fixed pairs new/in-game, diversity no back-to-back)	Met — sections B11–B15, C12–C14, E6–E7, F, G, H with sample session steps
Screenshots or notes for intentional UI differences	Met — “Intentional UI differences” table documents fork-only UI and rationale

Spot-checked references (ResumeActiveGame, PlayerPairSelect, heuristics.ts constants, etc.) — all accurate.

CI

CI failed on no repeated partners before full cycle (expected 0, received 4). Not related to this PR: branch is 1 commit ahead of main with only docs/VALIDATION.md changed; main CI is green. This is a probabilistic heuristic test flake, not a regression from these changes. Re-run or merge after CI green — not a docs content blocker.

Findings

• 🟢 Screenshot placeholders in “Intentional UI differences” are template stubs; notes table satisfies the issue requirement.
• 🟢 Checklist boxes are intentionally unchecked — appropriate for pre-release manual sign-off.