zcash-swift-wallet-sdk: Nullifier PIR integration

CHANGELOG.md

@@ -6,6 +6,35 @@ and this library adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
+## Added
+- Nullifier PIR (Private Information Retrieval) integration for Orchard note spendability detection without waiting for shard-tree scanning.
+  - `SpendabilityBackend` / `SpendabilityTypes` — Swift wrappers for the new Rust FFI.
+  - `Synchronizer.checkWalletSpendability` / `getPIRPendingSpends` — public API surface.
+  - `SDKFlags.pirCompleted` lifecycle flag.
+- Witness PIR integration for fetching Orchard note commitment witnesses from a PIR server, bypassing the shard-scanned gate and making notes immediately spendable.
+  - `WitnessBackend` / `WitnessTypes` — Swift wrappers for witness PIR FFI.
+  - `Synchronizer.fetchNoteWitnesses` / `getPIRWitnessedNotes` — public API surface.
+
+# 2.4.9 - 2026-04-04
+
+## Checkpoints
+
+Mainnet
+
+````
+Sources/ZcashLightClientKit/Resources/checkpoints/mainnet/3285000.json
+...
+Sources/ZcashLightClientKit/Resources/checkpoints/mainnet/3295000.json
+````
+
+Testnet
+
+````
+Sources/ZcashLightClientKit/Resources/checkpoints/testnet/3920000.json
+...
+Sources/ZcashLightClientKit/Resources/checkpoints/testnet/3930000.json
+````
+
 # 2.4.8 - 2026-03-25
 
 ## Fixed