Add PocketPay Mobile payment-period conduct guidance

[El-swaggerito]

Description

Difficulty: Hard

Type: Documentation

Summary

Add payment-period conduct guidance for PocketPay Mobile contributors.

Current Behaviour

Community channels can become noisy when contributors repeatedly complain about payments without checking whether their own work met the requirements.

Expected Behaviour

The repo should remind contributors to avoid spam, review their own contribution quality, and follow GrantFox communication processes.

Suggested Implementation

Add a short conduct note to contributor docs and README.

Files or Areas Likely Affected

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

Acceptance Criteria

• Payment-period conduct guidance is added.
• Repeated spam or complaints are discouraged.
• Contributors are asked to self-review first.
• GrantFox evaluation process is referenced.
• Tone is professional and firm.
• README links to the guidance.

Additional Notes

This directly addresses the community-spam concern.