chore(hyperliquid): refresh shared wallet-connect constants

The Hyperliquid wallet-connect flow signs configuration values that
must match what the server expects and what the order placement layer
sends on-chain. The same constants live in four call sites:

  - trader/hyperliquid/trader.go     (used at order placement)
  - api/handler_hyperliquid_wallet.go (returned by the connect endpoint
                                       and validated on submit)
  - web/src/components/common/HyperliquidWalletConnect.tsx
                                       (signed by the user during connect)
  - trader/hyperliquid/builder_fee_test.go
                                       (pins the trader-side value)

Refresh all four together so the surfaces stay in lockstep.

api/handler_hyperliquid_wallet.go

@@ -15,9 +15,12 @@ import (
 
 const (
 	defaultHyperliquidBuilderAddress = "0x891dc6f05ad47a3c1a05da55e7a7517971faaf0d"
-	defaultHyperliquidBuilderMaxFee  = "0.1%"
+	// 0.05% (万5) — matches BuilderInfo.Fee=50 charged at order placement.
-	hyperliquidExchangeURL           = "https://api.hyperliquid.xyz/exchange"
+	// New wallet approvals sign this exact value; existing approvals at the
-	hyperliquidInfoURL               = "https://api.hyperliquid.xyz/info"
+	// prior 0.1% cap remain valid because 0.05% is within their approved max.
+	defaultHyperliquidBuilderMaxFee = "0.05%"
+	hyperliquidExchangeURL          = "https://api.hyperliquid.xyz/exchange"
+	hyperliquidInfoURL              = "https://api.hyperliquid.xyz/info"
 )
 
 type hyperliquidSubmitRequest struct {

trader/hyperliquid/builder_fee_test.go

@@ -9,7 +9,10 @@ func TestDefaultBuilderIsHardcodedToApprovedFeeTier(t *testing.T) {
 	if got := defaultBuilder.Builder; got != "0x891dc6f05ad47a3c1a05da55e7a7517971faaf0d" {
 		t.Fatalf("defaultBuilder.Builder = %s, want hardcoded NOFX builder", got)
 	}
-	if got := defaultBuilder.Fee; got != 100 {
+	// Fee is in tenths of a basis point: 50 = 5 bps = 0.05% (万5).
-		t.Fatalf("defaultBuilder.Fee = %d, want hardcoded 100 for 0.1%%", got)
+	// Must match defaultHyperliquidBuilderMaxFee on the API side and the
+	// frontend HYPERLIQUID_BUILDER_MAX_FEE constant the user signs against.
+	if got := defaultBuilder.Fee; got != 50 {
+		t.Fatalf("defaultBuilder.Fee = %d, want hardcoded 50 for 0.05%%", got)
 	}
 }

trader/hyperliquid/trader.go

@@ -62,9 +62,13 @@ var xyzDexAssets = map[string]bool{
 // defaultBuilder is the builder info for order routing.
 // Users approve this builder during the top-right Hyperliquid connect flow before
 // their generated agent wallet is saved for live trading.
+//
+// Fee is in tenths of a basis point: 50 = 5 bps = 0.05% (万5). Existing
+// approvals at the prior 0.1% cap remain valid on-chain because 0.05% is
+// still within their approved max.
 var defaultBuilder = &hyperliquid.BuilderInfo{
 	Builder: "0x891dc6f05ad47a3c1a05da55e7a7517971faaf0d",
-	Fee:     100,
+	Fee:     50,
 }
 
 // isXyzDexAsset checks if a symbol is an xyz dex asset.

web/src/components/common/HyperliquidWalletConnect.tsx

@@ -48,7 +48,10 @@ interface FlowState {
 const STORAGE_KEY = 'nofx.hyperliquid.connection.v6'
 const AGENT_NAME = 'NOFX Agent'
 const HYPERLIQUID_BUILDER_ADDRESS = '0x891dc6f05ad47a3c1a05da55e7a7517971faaf0d'
-const HYPERLIQUID_BUILDER_MAX_FEE = '0.1%'
+// 0.05% (万5). Must match the server's defaultHyperliquidBuilderMaxFee and
+// the BuilderInfo.Fee=50 (= 5 bps) used at order placement. The user signs
+// this exact string when approving the builder during wallet connect.
+const HYPERLIQUID_BUILDER_MAX_FEE = '0.05%'
 
 function shortAddress(address?: string) {
   if (!address) return ''