docs: add documentation on how to use ramps staging environments

[cortisiko]

Description

Adds a new tests/docs/ONRAMP-PROVIDER-TESTING.md manual testing guide for staging on-ramp flows, covering required feature flags, where to find provider sandbox credentials, step-by-step walkthroughs for Transak (native) and MoonPay (WebView) checkouts, and basic troubleshooting.

Updates README.md to link to the new on-ramp provider testing document under Documentation.

Changelog

CHANGELOG entry:

Related issues

Fixes:

Manual testing steps

Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I've included tests if applicable
• I've documented my code using JSDoc format if applicable
• I've applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

---

Note

Low Risk
Low risk: documentation-only changes (new markdown guide and README link) with no runtime, security, or data-handling impact.

Overview
Adds a new tests/docs/ONRAMP-PROVIDER-TESTING.md guide describing how to manually validate staging on-ramp flows, including required feature flags, where to find provider sandbox credentials, step-by-step walkthroughs for Transak (native) and MoonPay (WebView), and troubleshooting.

Updates README.md to link to this new on-ramp provider manual testing documentation under Documentation.

^{Written by Cursor Bugbot for commit 1b3c081. This will update automatically on new commits. Configure here.}

[github-actions]

🔍 Smart E2E Test Selection

• Selected E2E tags: None (no tests recommended)
• Selected Performance tags: None (no tests recommended)
• Risk Level: low
• AI Confidence: 98%

click to see 🤖 AI reasoning details

E2E Test Selection:
The PR contains only documentation changes:

1. README.md: A single line addition to the documentation index, adding a link to a new on-ramp provider testing guide.

2. tests/docs/ONRAMP-PROVIDER-TESTING.md: A new 248-line markdown documentation file providing a manual testing guide for on-ramp providers (Transak and MoonPay). This is purely instructional documentation for manual QA testing, not automated E2E test code.

These changes:

• Do not modify any application code
• Do not modify any E2E test files or infrastructure
• Do not affect CI/CD workflows
• Do not change any test fixtures or page objects
• Are purely documentation/README updates

No E2E tests are needed because there is zero risk of breaking any functionality or existing tests. The documentation file is a manual testing guide that provides instructions for human testers, not automated test code.

Performance Test Selection:
These are pure documentation changes (README.md update and a new markdown testing guide). No application code, UI components, data loading, or any executable code was modified. There is no potential performance impact from documentation-only changes.

View GitHub Actions results

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud