docs: add initial README with usage and setup instructions

README.md

@@ -0,0 +1,181 @@
+# Polymarket SDK
+
+TypeScript SDK for building Polymarket proxy-wallet transaction payloads.
+
+This package does **NOT** send transactions. Instead, it returns deterministic `Transaction` objects containing:
+
+- `to`: contract address to target
+- `typeCode`: how the proxy wallet should execute the call (`Call` vs `DelegateCall`)
+- `data`: ABI-encoded calldata (`0x...`)
+- `value`: ETH value as a string
+
+## Install
+
+```bash
+pnpm add @polymarket/sdk
+```
+
+Node.js `>= 22` is required.
+
+## Key Concepts
+
+### Transaction builders
+
+The exported functions are **pure builders**:
+they take addresses/amounts/ids and produce `Transaction` objects (or `Transaction[]` bundles).
+
+Most higher-level workflows return multiple transactions, commonly:
+
+1. An approval transaction (ERC20 approve, or ERC1155 `setApprovalForAll`)
+2. The main action transaction (market addFunding/buy/sell, debt pay, etc.)
+
+### CallType
+
+`typeCode` comes from `src/types.ts`:
+
+- `CallType.Call` (`"1"`): normal `call`
+- `CallType.DelegateCall` (`"2"`): `delegatecall` semantics (meant to be executed by a proxy wallet that supports it)
+
+If a returned transaction uses `DelegateCall`, you generally should **not** submit it as a normal Ethereum transaction directly; execute it via the intended proxy wallet/executor.
+
+## Example: compute a proxy wallet address
+
+```ts
+import { getProxyWalletAddress } from "@polymarket/sdk";
+import type { Address } from "viem";
+
+const factory = "0x..."; // proxy wallet factory
+const user = "0x..."; // user address
+
+const proxyWallet = getProxyWalletAddress(factory as Address, user as Address);
+console.log(proxyWallet);
+```
+
+## Example: build a market purchase bundle
+
+```ts
+import { buyMarketOutcome } from "@polymarket/sdk";
+
+// fixed product market maker + collateral token
+const marketMaker = "0x..."; // FixedProductMarketMaker
+const collateralToken = "0x..."; // ERC20
+
+const investmentAmount = 1_000n * 10n ** 6n; // use bigint; decimals depend on token
+const outcomeIndex = 0n; // typically bigint
+const minOutcomeTokensToBuy = 900n * 10n ** 6n;
+
+const bundle = buyMarketOutcome(
+	marketMaker,
+	collateralToken,
+	investmentAmount,
+	outcomeIndex,
+	minOutcomeTokensToBuy,
+);
+
+// bundle is Transaction[]:
+// - [0] ERC20 approve(collateral -> marketMaker)
+// - [1] marketMaker.buy(...)
+```
+
+## Example: conditional tokens (split/merge/redeem)
+
+The SDK derives the partition from `outcomeSlotCount`:
+`[1n, 2n, 4n, ...]`.
+
+### Split
+
+```ts
+import { splitPosition } from "@polymarket/sdk";
+
+const txs = splitPosition(
+	"0x... (ConditionalTokens)",
+	"0x... (collateral token)",
+	"0x... (conditionId)",
+	2, // outcomeSlotCount
+	100n, // amount
+);
+```
+
+### Merge / Redeem
+
+```ts
+import { mergePositions, redeemPositions } from "@polymarket/sdk";
+
+const mergeTxs = mergePositions(CT, COLLATERAL, CONDITION_ID, 3, 500n);
+const redeemTxs = redeemPositions(CT, COLLATERAL, CONDITION_ID, 2);
+```
+
+## Example: debt workflows
+
+```ts
+import { takeOnDebt, payDebt } from "@polymarket/sdk";
+
+// takeOnDebt builds a single tx targeting the debt tracker
+const takeTxs = takeOnDebt("0x... (debtTracker)", 100n, "0x... (txHash)");
+
+// payDebt returns [approve, payDebt]
+const payTxs = payDebt("0x... (debtTracker)", "0x... (tokenAddress)", 50n);
+```
+
+## Example: negRisk adapter operations
+
+```ts
+import { negRiskOperations } from "@polymarket/sdk";
+
+const convertTx = negRiskOperations.convertPositions({
+	negRiskAdapterAddress: "0x... (adapter)",
+	marketId: "0x... (marketId)",
+	indexSet: 5n,
+	amount: 2_000n,
+});
+
+const redeemTx = negRiskOperations.redeemPositions({
+	negRiskAdapterAddress: "0x... (adapter)",
+	conditionId: "0x... (conditionId)",
+	amounts: [750n, 250n],
+});
+```
+
+## Example: UMA adapter initialization
+
+```ts
+import { initialize, negRiskInitialize } from "@polymarket/sdk/adapter";
+// Note: depending on your bundler, you may instead import from package root.
+
+const tx = initialize(
+	"0x... (adapter address)",
+	new Uint8Array([]), // ancillaryData
+	"0x... (reward token)",
+	1n, // reward
+	1n, // proposalBond
+);
+
+const negTx = negRiskInitialize(
+	"0x... (adapter address)",
+	new Uint8Array([]),
+	"0x... (reward token)",
+	1n,
+	1n,
+	100n, // liveness
+);
+```
+
+## Utilities
+
+```ts
+import { getIndexSet, getMarketIndex } from "@polymarket/sdk";
+
+const indexSet = getIndexSet([0, 2, 3]); // bigint bitset
+const marketIndex = getMarketIndex("0x... questionId");
+```
+
+Other helpers:
+
+- `erc20ApprovalTransaction(tokenAddress, spender, amount)`
+- `erc1155ApprovalTransaction(tokenAddress, spender, approval)`
+- `erc20TransferTransaction(tokenAddress, recipient, amount)`
+- `ethTransferTransaction(recipient, amount)`
+
+## License
+
+MIT