BUG: Fixed interruption in route_base_rewards (#35)

There was an issue in the BaseRewardRouter where if max_iterations was
hit, it would not carry over the `rewards_to_process` meaning when the
instruction ran again, it would go off of the new pre-routed value.

Say we had 10 operators and 5 max_iterations with 10_000 rewards to
split:

```
op0: 1000
op1: 1000
op2: 1000
op3: 1000
- Iterations Hit -
op4: 600
op5: 600
op6: 600
op7: 600
op8: 600
op9: 600
```

The fix was to save the `last_rewards_to_process` like we do in
route_ncn_rewards;

clients/js/jito_tip_router/accounts/baseRewardRouter.ts

@@ -59,6 +59,7 @@ export type BaseRewardRouter = {
   reserved: Array<number>;
   lastNcnGroupIndex: number;
   lastVoteIndex: number;
+  lastRewardsToProcess: bigint;
   baseFeeGroupRewards: Array<BaseRewardRouterRewards>;
   ncnFeeGroupRewards: Array<BaseRewardRouterRewards>;
   ncnFeeGroupRewardRoutes: Array<NcnRewardRoute>;
@@ -76,6 +77,7 @@ export type BaseRewardRouterArgs = {
   reserved: Array<number>;
   lastNcnGroupIndex: number;
   lastVoteIndex: number;
+  lastRewardsToProcess: number | bigint;
   baseFeeGroupRewards: Array<BaseRewardRouterRewardsArgs>;
   ncnFeeGroupRewards: Array<BaseRewardRouterRewardsArgs>;
   ncnFeeGroupRewardRoutes: Array<NcnRewardRouteArgs>;
@@ -94,6 +96,7 @@ export function getBaseRewardRouterEncoder(): Encoder<BaseRewardRouterArgs> {
     ['reserved', getArrayEncoder(getU8Encoder(), { size: 128 })],
     ['lastNcnGroupIndex', getU8Encoder()],
     ['lastVoteIndex', getU16Encoder()],
+    ['lastRewardsToProcess', getU64Encoder()],
     [
       'baseFeeGroupRewards',
       getArrayEncoder(getBaseRewardRouterRewardsEncoder(), { size: 8 }),
@@ -122,6 +125,7 @@ export function getBaseRewardRouterDecoder(): Decoder<BaseRewardRouter> {
     ['reserved', getArrayDecoder(getU8Decoder(), { size: 128 })],
     ['lastNcnGroupIndex', getU8Decoder()],
     ['lastVoteIndex', getU16Decoder()],
+    ['lastRewardsToProcess', getU64Decoder()],
     [
       'baseFeeGroupRewards',
       getArrayDecoder(getBaseRewardRouterRewardsDecoder(), { size: 8 }),

clients/rust/jito_tip_router/src/generated/accounts/base_reward_router.rs

@@ -28,6 +28,7 @@ pub struct BaseRewardRouter {
     pub reserved: [u8; 128],
     pub last_ncn_group_index: u8,
     pub last_vote_index: u16,
+    pub last_rewards_to_process: u64,
     pub base_fee_group_rewards: [BaseRewardRouterRewards; 8],
     pub ncn_fee_group_rewards: [BaseRewardRouterRewards; 8],
     #[cfg_attr(feature = "serde", serde(with = "serde_big_array::BigArray"))]