…overhead and prevent leaks cp-7.63.0 cp-7.64.0 (#25496)

## **Description**

This PR addresses WebSocket subscription issues identified during the
rate limiting incident investigation. The fixes reduce subscription
message volume by ~75% and prevent subscription leaks.

### Root Causes Identified

1. **Subscriptions to unregistered DEXs** - System subscribed to ALL 8
DEXs from API instead of only the 2 in our allowlist (main + xyz)
2. **Duplicate DEX subscriptions from race conditions** - Concurrent
calls created 2× subscriptions per DEX
3. **Candle subscription leaks** - Cleanup failed when component
unmounted before async subscription resolved

### Fixes Implemented

#### 1. Filter DEXs by Allowlist on Mainnet (HIGH PRIORITY)
**Files:** `hyperLiquidConfig.ts`, `HyperLiquidProvider.ts`

- Added `MAINNET_HIP3_CONFIG` with `AutoDiscoverAll: false`
- DEX filtering is now dynamic - extracts DEX names from the
`allowlistMarkets` feature flag patterns
- Added `extractDexsFromAllowlist()` method that parses patterns like
`xyz:*`, `xyz:TSLA`, or `xyz`
- **Impact:** Reduces from 8 DEXs to 2 (main + xyz), ~75% reduction in
subscription messages

#### 2. Prevent Duplicate DEX Subscriptions (HIGH PRIORITY)
**File:** `HyperLiquidSubscriptionService.ts`

- Added `pendingClearinghouseSubscriptions` and
`pendingOpenOrdersSubscriptions` Maps
- Refactored `ensureClearinghouseStateSubscription()` and
`ensureOpenOrdersSubscription()` to check for pending promises
- Concurrent calls now wait for the pending promise instead of creating
duplicate subscriptions
- **Impact:** Prevents 50% redundant subscriptions from race conditions

#### 3. Fix Candle Subscription Cleanup (HIGH PRIORITY)
**File:** `HyperLiquidClientService.ts`

- Store subscription promise to enable cleanup even when pending
- Updated cleanup function to wait for pending promise and unsubscribe
- **Impact:** Prevents WebSocket subscription leaks when component
unmounts before subscription resolves

### Test Results

| Metric | Before | After | Improvement |
|--------|--------|-------|-------------|
| DEXs subscribed | 8 | 2 | 75% reduction |
| clearinghouseState subscriptions | 16 | 2 | 87% reduction |
| openOrders subscriptions | 16 | 2 | 87% reduction |
| Candle subscription leaks | Yes | No | Fixed |

## **Changelog**

CHANGELOG entry: null

## **Related issues**

Fixes: Rate limiting incident from WebSocket over-subscription

Related: [WebSocket Subscription Investigation
Report](docs/perps/perps-websocket-subscription-investigation.md)

## **Manual testing steps**

```gherkin
Feature: WebSocket subscription optimization

  Scenario: User connects to perps and only allowlisted DEXs are subscribed
    Given user has the app installed with perps feature enabled
    And WebSocket logging is enabled in dev mode

    When user navigates to Perps home screen
    Then WebSocket logs show subscriptions only for main and xyz DEXs
    And no subscriptions for flx, vntl, hyna, km, abcd, cash DEXs

  Scenario: User navigates between markets without duplicate subscriptions
    Given user is connected to perps
    And WebSocket logging is enabled

    When user navigates from Home to xyz:XYZ100 market details
    And user returns to Home
    And user navigates back to xyz:XYZ100
    Then WebSocket logs show no duplicate clearinghouseState subscriptions
    And WebSocket logs show no duplicate openOrders subscriptions

  Scenario: User views candle chart and subscriptions are properly cleaned up
    Given user is on a market details screen with chart visible

    When user quickly navigates away from the screen
    And user waits for 2 seconds
    Then candle subscriptions are properly unsubscribed
    And no orphaned candle subscriptions exist
```

## **Screenshots/Recordings**

### **Before**

WebSocket subscription breakdown (full trading flow):
- clearinghouseState: 16 subscriptions (8 DEXs × 2 duplicates)
- openOrders: 16 subscriptions (8 DEXs × 2 duplicates)
- candle: 4 subscriptions, 0 unsubscriptions (leak)

### **After**

WebSocket subscription breakdown (full trading flow):
- clearinghouseState: 2 subscriptions (main + xyz only)
- openOrders: 2 subscriptions (main + xyz only)
- candle: 2 subscriptions, 2 unsubscriptions (balanced)

**Total outgoing messages:** 44
**Total incoming messages:** 402 (down from ~750)

## **Pre-merge author checklist**

- [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
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
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.

---

### Subscription Breakdown
- `clearinghouseState`: 2 (main + xyz)
- `openOrders`: 2 (main + xyz)
- `userFills`: 1
- `webData3`: 1
- `allMids`: 1
- `assetCtxs`: 2 (xyz only, subscribed/unsubscribed on navigation)
- `activeAssetCtx`: 2 (xyz:XYZ100, subscribed/unsubscribed on
navigation)
- `candle`: 2 (1h + 15m intervals)
- `bbo`: 2 (subscribed/unsubscribed during order flow)

### Future Optimization Opportunity

Trading operations (order placement, cancellation, modification)
currently use **HTTP transport**:
- `ExchangeClient` is configured with `httpTransport` to avoid 429 rate
limiting
- `InfoClient` uses `wsTransport` for info queries (multiplexed over
single WS connection)

Now that subscription volume is reduced by 75%, we could consider moving
`ExchangeClient` to WebSocket transport (see follow-up investigation).

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Touches core perps WebSocket subscription and DEX-discovery behavior;
bugs could lead to missing market data or stale positions/orders, though
changes are localized and defensive.
> 
> **Overview**
> Reduces perps WebSocket load by **filtering mainnet HIP-3 DEX
discovery/subscription based on the `allowlistMarkets` feature flag**,
falling back to main DEX only when no HIP-3 patterns are allowlisted
(via new `MAINNET_HIP3_CONFIG` and allowlist DEX parsing in
`HyperLiquidProvider`).
> 
> Prevents subscription churn/leaks by **deduplicating concurrent
`clearinghouseState`/`openOrders` subscriptions** with pending-promise
tracking in `HyperLiquidSubscriptionService`, and by **fixing candle
unsubscription when the async subscribe promise hasn’t resolved yet** in
`HyperLiquidClientService`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
73e62ff. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Claude <noreply@anthropic.com>