v2.1.0: Full API alignment with Polymarket CLOB V2

What's New

New Packages

• Relayer API (pkg/relayer): 7 endpoints for gasless transactions (Submit, GetTransaction, GetTransactions, GetNonce, GetRelayPayload, GetDeployed, GetAPIKeys)
• Combo Markets API (pkg/combo): combo market queries

New CLOB Endpoints (8)

• ClobMarketInfo — CLOB-level market parameters
• MarketByToken — reverse token→market lookup
• MarketsLiveActivity / MarketLiveActivity — batch/single live activity
• BatchPricesHistory — batch historical prices
• OrderBooksQuery — order books via query params
• NegRiskByPath — neg risk via path param
• PutBalanceAllowance — force update balance/allowance

Bridge Completions (2)

• Quote — bridge quote
• WithdrawAddress — create withdrawal bridge addresses

Data API Additions (4)

• AccountingSnapshot — download accounting ZIP
• MarketPositions — positions for a specific market
• ActivityCombos — combo activity
• PositionsCombos — combo positions

Gamma Addition (1)

• TeamByID — single team lookup

Fix

• Order payload wire format: salt and timestamp now correctly sent as JSON strings for ALL signature types, matching Polymarket V2 API specification

Dependencies

• aws-sdk-go-v2/service/kms: 1.52.0 → 1.53.4

All 19 packages pass tests and go vet.