docs: add changeset

Author: solidsnakedev

.changeset/cruel-rice-sort.md

@@ -0,0 +1,50 @@
+---
+"@evolution-sdk/devnet": patch
+"@evolution-sdk/evolution": patch
+---
+
+Migrate transaction builder and provider layer to use Core UTxO types throughout the SDK.
+
+### New Core Types
+
+- **`Core.UTxO`** — Schema-validated UTxO with branded types (`TransactionHash`, `Address`, `Assets`)
+- **`Core.Assets`** — Enhanced with `merge`, `subtract`, `negate`, `getAsset`, `setAsset`, `hasAsset` operations
+- **`Core.Time`** — New module for slot/time conversions with `SlotConfig`, `Slot`, `UnixTime`
+- **`Core.Address`** — Added `getAddressDetails`, `getPaymentCredential`, `getStakingCredential` utilities
+
+### SDK Changes
+
+- Provider methods (`getUtxos`, `getUtxoByUnit`, `getUtxosWithUnit`) now return `Core.UTxO.UTxO[]`
+- Client methods (`getWalletUtxos`, `newTx`) use Core UTxO internally
+- Transaction builder accepts `Core.UTxO.UTxO[]` for `availableUtxos`
+- `Genesis.calculateUtxosFromConfig` and `Genesis.queryUtxos` return Core UTxOs
+
+### Rationale
+
+The SDK previously used a lightweight `{ txHash, outputIndex, address, assets }` record for UTxOs, requiring constant conversions when interfacing with the Core layer (transaction building, CBOR serialization). This caused:
+
+1. **Conversion overhead** — Every transaction build required converting SDK UTxOs to Core types
+2. **Type ambiguity** — `txHash: string` vs `TransactionHash`, `address: string` vs `Address` led to runtime errors
+3. **Inconsistent APIs** — Some methods returned Core types, others SDK types
+
+By standardizing on Core UTxO:
+
+- **Zero conversion** — UTxOs flow directly from provider → wallet → builder → transaction
+- **Type safety** — Branded types prevent mixing up transaction hashes, addresses, policy IDs
+- **Unified model** — Single UTxO representation across the entire SDK
+
+### Migration
+
+```typescript
+// Before
+const lovelace = Assets.getAsset(utxo.assets, "lovelace")
+const txId = utxo.txHash
+const idx = utxo.outputIndex
+const addr = utxo.address // string
+
+// After  
+const lovelace = utxo.assets.lovelace
+const txId = Core.TransactionHash.toHex(utxo.transactionId)
+const idx = utxo.index // bigint
+const addr = Core.Address.toBech32(utxo.address) // or use Address directly
+```