Add PocketPay SDK payment-period communication policy

[El-swaggerito]

Description

Difficulty: Hard

Type: Documentation

Summary

Add a payment-period communication policy for PocketPay SDK contributors.

Current Behaviour

Community channels may be flooded with repeated complaints when contributors expect automatic payment after merge.

Expected Behaviour

The repo should remind contributors to avoid spam, review their own contribution quality, and follow the GrantFox evaluation process.

Suggested Implementation

Add a short conduct policy to contributor documentation and README.

Files or Areas Likely Affected

• src/
• tests/
• docs/
• README.md
• .github/
• package.json

Acceptance Criteria

• Payment-period communication policy is added.
• Repeated spam or complaints are discouraged.
• Contributors are asked to self-review before raising payment concerns.
• GrantFox evaluation process is referenced.
• Tone is professional and firm.
• README links to the policy.

Additional Notes

This directly addresses payment-period community behaviour.