v1.13.0 - 2025-12-16

Added

New endpoint: PATCH /limit for editing existing limit orders
- Purpose: Modify price and size of existing orders without canceling and resubmitting
- Benefits: Atomic updates preserve queue position for unchanged price, reduced latency for order modifications
- Authentication: Requires EIP-712 signature (one-click sessions not supported)
Request example (options):
```
const editRequest = {
  order_id: "abc123def456...",
  price: 2600.0,           // New price
  contracts: 2.0,          // New size for options
  signature: "0x...",
  signature_deadline: 1735689600
};

const response = await fetch('/limit', {
  method: 'PATCH',
  headers: {
    'x-apikey': API_KEY,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify(editRequest)
});
```
Request example (perpetuals):
```
const editRequest = {
  order_id: "abc123def456...",
  price: 98500.0,          // New price
  amount: 15000,           // New size for perpetuals
  signature: "0x...",
  signature_deadline: 1735689600
};
```
Constraints:
- Order must exist and belong to the signing maker
- Cannot edit orders during active MMP freeze
- Must edit within the same market as original order
- Size must meet minimum increment requirements
Response: Returns the updated StoredLimitOrder with new values and edit_order event emitted on WebSocket

Changed

Correction: WebSocket trade events do not include order metadata

Trade events contain execution data only. The following fields are not present on trade events:

user_id - Use order events for user tracking
order_size - Use order events for original order size
filled_amount - Use order events for cumulative fill tracking

Trade event structure (actual):

{
  "kind": "event",
  "type": "trade",
  "timestamp_ms": 1734355200000,
  "data": {
    "margin_account_id": "550e8400-e29b-41d4-a716-446655440000",
    "smart_account_address": "0x1234567890abcdef1234567890abcdef12345678",
    "trade_id": "1234567890abcdef1234567890abcdef",
    "order_id": "abcdef1234567890abcdef1234567890",
    "size": 1.5,
    "timestamp": 1734355200000,
    "direction": "buy",
    "index_price": 45000.5,
    "instrument_name": "BTC_USDC-31DEC25-100000-C",
    "average_price": 2500.0,
    "limit_price": 2500.0,
    "liquidation": false,
    "iv": 0.65,
    "taker_fee": 0.50,
    "maker_fee": 0.25,
    "systemic_risk_fee": 0.10,
    "liquidation_fee": 0.0,
    "realised_funding": 0.0
  }
}

Migration: For order lifecycle metadata including user_id, total order size, and cumulative filled_amount, subscribe to order events (post_order, update_order, cancel_order) via orderbook channels.

WebSocket order events now include user_id field

Order events (post_order, cancel_order, update_order, edit_order) include the user_id field when provided during order submission:
```
{
  "kind": "event",
  "type": "post_order",
  "data": {
    "instrument_name": "BTC_USDC-31DEC25-100000-C",
    "order_id": "abc123...",
    "user_id": "trader_001",
    "maker": "0x1234...",
    ...
  }
}
```
Benefits: Track orders across their full lifecycle using your custom identifiers

Fixed

POST /limit error messages now match backend validation exactly:
- Added: "order size not divisible by minimum increment"
- Fixed: "multiple markets provided" message formatting
PATCH /limit error messages aligned with ORDERBOOK_API_ERROR_MESSAGES constants