chore(runway): cherry-pick fix(ramps): Preserve user-entered amount during Transak navigation reset -> cp-7.71.0

[runway-github]

• fix(ramps): Preserve user-entered amount during Transak navigation reset -> cp-7.71.0 (fix(ramps): Preserve user-entered amount during Transak navigation reset -> cp-7.71.0 #27742)

Description

Fixes the Buy flow amount reverting from the user-entered value back to
the default $100 during the Transak native provider loading transition.

When a user enters a custom amount (e.g. $30) and taps Continue, the
Transak routing callbacks use navigation.reset() to rebuild the
navigation stack with a fresh BuildQuote screen as the base route.
This fresh instance initialized with DEFAULT_AMOUNT = 100, causing a
visible flash of $100 during the transition to the checkout/KYC screen.

The fix passes the current quote.fiatAmount as a route param
(amount) to the AMOUNT_INPUT base route in every
navigation.reset() call. BuildQuote now reads params?.amount as
the initial state, preserving the user-entered amount through stack
resets.

Changelog

CHANGELOG entry: Fixed Buy flow amount input reverting to $100 during
Transak native provider checkout transition.

Related issues

Fixes:
TRAM-3348

Manual testing steps

Feature: Amount persists through Transak native provider checkout transition

  Scenario: Custom amount does not revert to default during Continue loading
    Given the user is on the Buy screen with Transak Native provider
    And the default amount is $100
    When the user changes the amount to $30
    And the user taps Continue
    Then the displayed amount remains $30 during the loading transition
    And the amount does not flash back to $100

  Scenario: Default amount is preserved when no custom amount is entered
    Given the user is on the Buy screen with Transak Native provider
    And the default amount is $100
    When the user taps Continue without changing the amount
    Then the displayed amount remains $100 throughout the flow

  Scenario: Amount persists when navigating back from KYC/checkout screens
    Given the user entered $50 and proceeded through Continue
    When the user navigates back to the Buy screen
    Then the amount input shows $50 (not $100)

Screenshots/Recordings

Before

ScreenRecording_03-12-2026.10-21-58_1.MP4

After

Screen.Recording.2026-03-20.164415.mp4

Screen.Recording.2026-03-20.174939.mp4

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

Medium Risk
Updates Transak native-provider navigation/reset logic and initial
screen state; mistakes could regress Buy/KYC routing or amount display
during transitions, but changes are localized and covered by tests.

Overview
Fixes the Transak native Buy flow so the user-entered fiat amount is
preserved when the app uses navigation.reset() during KYC/checkout
transitions.

BuildQuote now supports an amount route param to initialize the
amount state (and to prevent region defaults from overriding it), and
useTransakRouting propagates this amount through all reset-based
navigation paths (KYC approved → checkout, KYC forms, additional
verification, verify identity, and KYC webview). Tests are updated/added
to assert the amount is passed through routing callbacks and used as the
initial displayed value.

^{Written by Cursor
Bugbot for commit
a8bdee0. This will update automatically
on new commits. Configure
here.}

[8a03f66](https://github.com/MetaMask/metamask-mobile/commit/8a03f66803964cbbe25b37cde717aeed03ec4bf7)

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[github-actions]

🔍 Smart E2E Test Selection

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

✅ E2E Fixture Validation — Schema is up to date
15 value mismatches detected (expected — fixture represents an existing user).
View details

[chloeYue]

LGTM