docs: add contributor evaluation policy

[fredericjasmin]

Summary

Closes #137

Adds a dedicated Contributor Evaluation Policy that centralizes contributor evaluation expectations while reusing the repository's existing documentation. The policy explains the post-merge GrantFox evaluation process, links contributors to the appropriate review, testing, and payment guidance, and is now discoverable from the README.

PR Evidence Checklist

Before requesting review, confirm the following evidence is present in this PR description. Each item links to detailed guidance. PRs missing evidence will be sent back for completion.

• Issue reference: PR body links the issue with Closes #NNN.
• Implementation summary: 1–3 sentence description of what changed and why.
• Tests added or updated: Documentation-only change; no tests required.
• Commands run: pnpm format:check; manual verification of documentation links.
• CI status: Pending.
• Acceptance criteria coverage: Included below.

Issue scope

Acceptance Criterion	Status	Implementation Evidence	Tests	Notes
Policy states merged PRs do not guarantee payment approval	✅	New docs/CONTRIBUTOR_EVALUATION_POLICY.md	Documentation review
GrantFox evaluation process referenced clearly	✅	New policy links to GRANTFOX_WORKFLOW.md	Documentation review
Contributors are told not to spam community channels during payment periods	✅	New policy references payment-period communication guidance	Documentation review
Testing and CI expectations are included	✅	New policy references testing, CI, and verification guides	Documentation review
Acceptance criteria completion is included	✅	New policy references acceptance criteria documentation	Documentation review
README links to the policy	✅	Added policy to README docs index and GrantFox readiness section	Documentation review

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

• pnpm format:check
• Verified all referenced documentation links resolve correctly.
• No runtime tests were required because this PR only adds and updates documentation.
• CI status: Pending.

Screenshots / recordings

Before	After
N/A	N/A

Security impact

• No security-relevant surface touched.

Documentation-only change.

Documentation impact

• Docs under /docs updated for this change.
• README updated (new package, script, or workflow).
• No user-facing behaviour changed — no docs update needed.

Maintainer Review Checklist (self-check)

PR self-check

• References the original issue with Closes #NNN in the PR body.
• Acceptance criteria on the issue are checked off individually in the PR description.
• pnpm verify passes locally (documentation-only change).
• pnpm check:boundaries passes locally (not applicable).
• 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

• Documentation-only change; no tests required.

Documentation

• Topic docs updated for new contributor guidance.
• README documentation index updated.
• Security docs updated if new threat areas introduced.

Risk / follow-ups

None.

Acceptance Criteria Audit

The acceptance criteria completion table above covers all issue requirements.

GrantFox payment expectations

Merge does not guarantee payment approval. GrantFox evaluation occurs after merge and depends on implementation quality, acceptance criteria completion, testing evidence, CI status, and reviewer assessment.

Contributor self-review

Completed. The new policy acts as a lightweight entry point, reuses existing documentation instead of duplicating it, updates the README for discoverability, and remains within the scope of the issue.