docs: add PR reviewer evidence checklist (#163)

[fredericjasmin]

Summary

Closes #163

Adds a concise PR reviewer evidence checklist for AnchorKit maintainers. The checklist provides a central reference for reviewing implementation scope, implementation quality, test evidence, CI status, documentation impact, acceptance criteria, and implementation risk while linking to the existing canonical documentation instead of duplicating guidance.

Issue scope

Acceptance Criterion	Status	Implementation Evidence	Tests	Notes
Reviewer evidence checklist is added.	✅ Completed	Added docs/REVIEWER_EVIDENCE_CHECKLIST.md.	N/A (documentation)	Central reviewer reference.
Implementation scope is checked.	✅ Completed	Checklist includes implementation scope verification.	N/A	References existing review guidance.
Test evidence is checked.	✅ Completed	Checklist references existing testing evidence documentation.	N/A
CI status is checked.	✅ Completed	Checklist references existing CI guidance.	N/A
Acceptance criteria are checked.	✅ Completed	Checklist references acceptance criteria documentation.	N/A
README links to reviewer guidance.	✅ Completed	Added the new checklist to the README documentation index.	N/A

Affected packages / apps

• apps/web
• packages/types
• packages/config
• packages/fixtures
• packages/validators
• packages/stellar-kit
• packages/anchor-utils
• contracts/treasury-escrow
• docs/
• Other (list):

Testing performed

Commands executed:

• pnpm test ✅ Passed (all TypeScript tests passed)
• pnpm verify ⚠️ Could not complete successfully because the Rust cargo toolchain is unavailable in the current environment. Remaining reported issues are pre-existing and unrelated to this documentation-only change.

This PR only introduces documentation changes and does not modify runtime behavior.

Screenshots / recordings

N/A

Security impact

• No security-relevant surface touched.

Documentation impact

• Docs under /docs updated for this change.
• README updated.
• No user-facing behaviour changed — no docs update needed.

Maintainer Review Checklist (self-check)

PR self-check

• References the original issue with Closes #163 in the PR body.
• Acceptance criteria on the issue are checked off individually in the PR description.
• pnpm verify passes locally (Rust toolchain unavailable in the current environment).
• pnpm check:boundaries passes locally (not applicable for this documentation-only change).
• pnpm contract:test passes locally (not applicable).

Stellar network correctness

Not applicable.

Anchor and SEP flow correctness

Not applicable.

Payment intent and readiness correctness

Not applicable.

Soroban contract correctness (if contracts/ changed)

Not applicable.

Secret leakage (R0–R6)

Not applicable.

Mainnet safety

Not applicable.

Tests

Not applicable (documentation-only change).

Documentation

• Topic docs updated.
• README docs index updated.
• Security docs updated if new threat areas introduced.

Risk / follow-ups

None.

Acceptance Criteria Audit

All acceptance criteria for Issue #163 have been completed.

GrantFox payment expectations

Acknowledged.

Contributor self-review

Documentation-only change with a minimal diff. The implementation adds a reviewer evidence checklist, updates the README documentation index, reuses existing documentation instead of duplicating guidance, and does not change application behavior.