feat: add price alerts basic setup (MetaMask#31477)

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## **Description**

Adds the initial implementation of **Price Alerts** behind the
`priceAlertsEnabled` remote feature flag (version-gated).

When enabled, a notification icon appears in the Token Details header
for any token with a known price. Tapping it opens a manage view that
either shows existing alerts or drops straight into the create flow if
none exist yet.

The create screen lets users set a target price via a keypad or
quick-percentage pills (5/10/20/30%), toggle whether the alert repeats,
and see a live ± % indicator against the current price. On save the
alert is POSTed to `https://price-alerts.api.cx.metamask.io` using a
bearer token from `AuthenticationController`.

Delete and toggle-active actions in the manage view are stubbed for a
follow-up PR, as is the "Price change" alert type tab.

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## **Changelog**

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CHANGELOG entry: add price alerts basic setup

## **Related issues**

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Fixes: https://consensyssoftware.atlassian.net/browse/ASSETS-3351

## **Manual testing steps**

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```gherkin
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**

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<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

No price alerts support

### **After**



https://github.com/user-attachments/assets/142f2842-0cd5-4692-b013-00566257e36b



## **Pre-merge author checklist**

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- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I've included tests if applicable
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if applicable
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guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

#### Performance checks (if applicable)

- [x] I've tested on Android
  - Ideally on a mid-range device; emulator is acceptable
- [x] I've tested with a power user scenario
- Use these [power-user
SRPs](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/edit-v2/401401446401?draftShareId=9d77e1e1-4bdc-4be1-9ebb-ccd916988d93)
to import wallets with many accounts and tokens
- [x] I've instrumented key operations with Sentry traces for production
performance metrics
- See [`trace()`](/app/util/trace.ts) for usage and
[`addToken`](/app/components/Views/AddAsset/components/AddCustomToken/AddCustomToken.tsx#L274)
for an example

For performance guidelines and tooling, see the [Performance
Guide](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/400085549067/Performance+Guide+for+Engineers).

## **Pre-merge reviewer checklist**

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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> New authenticated backend integration (bearer token) for user alert
CRUD on token flows; mitigated by remote flag gating and incomplete
manage mutations (delete/toggle TODO).
> 
> **Overview**
> Introduces **price alerts** behind the version-gated remote flag
`priceAlertsEnabled`. When on, Token Details shows a notification
control (only if price &gt; 0 and CAIP-19 `assetId` resolves) that opens
**manage** or **create** flows for that asset.
> 
> **Create** supports “price reaches” with a keypad, quick ±5/10/20/30%
pills, recurring toggle, and live % vs current price; saves via
authenticated `POST` to the price-alerts API (`asset`, `threshold`,
`recurring`). **Manage** loads alerts per asset (React Query), replaces
into create when the list is empty or fetch fails, and lists thresholds
with recurring/once labels—**delete** and **active toggle** are UI-only
stubs. A second tab (“price change”) shows an under-development
placeholder.
> 
> Wiring adds `PRICE_ALERTS_API_URL` / `AppConstants.PRICE_ALERTS_API`,
navigation routes and screens, i18n, feature-flag registry entry, and
broad unit test coverage.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
8ee8d6b. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: juanmigdr

.js.env.example

@@ -80,6 +80,9 @@ export DECODING_API_URL: 'https://signature-insights.api.cx.metamask.io/v1'
 # URL of security alerts API used to validate dApp requests.
 export SECURITY_ALERTS_API_URL="https://security-alerts.api.cx.metamask.io"
 
+# URL of the price alerts API. Override to http://localhost:3333 for local dev.
+export PRICE_ALERTS_API_URL="https://price-alerts.dev-api.cx.metamask.io"
+
 # URL of the compliance API used for wallet compliance checks.
 export COMPLIANCE_API_URL="https://compliance.api.cx.metamask.io"
 

app/components/Nav/Main/MainNavigator.js

@@ -171,6 +171,8 @@ import RewardsSelectSheet from '../../UI/Rewards/components/RewardsSelectSheet';
 
 import SitesFullView from '../../Views/SitesFullView/SitesFullView';
 import { TokenDetails } from '../../UI/TokenDetails/Views/TokenDetails';
+import CreatePriceAlertView from '../../UI/Assets/PriceAlerts/Views/CreatePriceAlertView/CreatePriceAlertView';
+import ManagePriceAlertsView from '../../UI/Assets/PriceAlerts/Views/ManagePriceAlertsView/ManagePriceAlertsView';
 import BenefitFullView from '../../UI/Rewards/Views/BenefitFullView';
 import BenefitsFullView from '../../UI/Rewards/Views/BenefitsFullView';
 import MoneyTabPressTracker from '../../UI/Money/components/MoneyTabPressTracker';
@@ -211,6 +213,14 @@ const AssetStackFlow = (props) => (
       name={Routes.TRANSACTION_DETAILS}
       component={TransactionDetails}
     />
+    <NativeStack.Screen
+      name={Routes.CREATE_PRICE_ALERT}
+      component={CreatePriceAlertView}
+    />
+    <NativeStack.Screen
+      name={Routes.MANAGE_PRICE_ALERTS}
+      component={ManagePriceAlertsView}
+    />
   </NativeStack.Navigator>
 );
 

app/components/UI/AssetOverview/TokenOverview.testIds.ts

@@ -3,6 +3,7 @@ import enContent from '../../../../locales/languages/en.json';
 export const TokenOverviewSelectorsIDs = {
   CONTAINER: 'token-asset-overview',
   TOKEN_PRICE: 'token-price',
+  PRICE_ALERT_BUTTON: 'token-price-alert-button',
   SEND_BUTTON: 'token-send-button',
   RECEIVE_BUTTON: 'token-receive-button',
   BUY_BUTTON: 'token-buy-button',