fix(rewards): localize campaign date

[sophieqgu]

Description

Changelog

CHANGELOG entry: null

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]

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After

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---

Note

Low Risk
Low risk: swaps a hardcoded month-name formatter for cached Intl.DateTimeFormat using the app locale, plus a small Jest mock adjustment; behavior changes are limited to date label rendering.

Overview
Campaign tile date labels are now localized by formatting month/day via getIntlDateTimeFormatter using I18n.locale, replacing the prior hardcoded English month list.

Tests were updated to mock the i18n module’s default export (locale) so the new locale-aware formatter can run under Jest.

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🔍 Smart E2E Test Selection

• Selected E2E tags: None (no tests recommended)
• Selected Performance tags: None (no tests recommended)
• Risk Level: low
• AI Confidence: 95%

click to see 🤖 AI reasoning details

E2E Test Selection:
The changes are limited to two files in the Rewards/Campaigns UI utility layer:

1. CampaignTile.utils.ts: Replaces a hardcoded English MONTHS array with getIntlDateTimeFormatter (Intl.DateTimeFormat API) for locale-aware date formatting. This is a pure localization improvement with no behavioral change for English users and no impact on any shared infrastructure, navigation, controllers, or Engine.

2. CampaignTile.utils.test.ts: Updates the i18n mock to properly handle the new default export (I18n.locale) alongside the named strings export.

No E2E tests exist for the Rewards/Campaigns area. The change is a self-contained utility refactor covered by unit tests. It does not affect any critical paths (confirmations, swaps, accounts, network, browser, snaps, etc.), shared components (TabBar, modals, navigation), or any controller/Engine code. The risk is low and no E2E tags are warranted.

Performance Test Selection:
The change is a date formatting utility refactor (replacing a static array with Intl.DateTimeFormat). This has no impact on rendering performance, data loading, state management, or any performance-sensitive code paths. No performance tests are needed.

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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