fix: claim rewards pipeline uses the rollup fee asset, not the staking asset

[aminsammara]

Problem

Sequencer rewards are paid in the rollup's fee asset — RewardLib.claimSequencerRewards does rollupStore.config.feeAsset.safeTransfer(_sequencer, amount). The dashboard's entire claim pipeline instead used StakingRegistry.STAKING_ASSET as the reward token.

On mainnet feeAsset == stakingAsset, so this happened to work. On testnet they are different tokens ("FeeJuice" vs "Staking"), which breaks the flow:

• claimSequencerRewards moves FEE onto the split contract ✅
• Split.distribute(..., STK, ...) distributes the split's STK balance, which is 0 — the tx succeeds but distributes nothing
• the FEE rewards sit stranded on the PullSplit, and the dashboard can't even see them (the stranded-balance recovery check also reads the STK balance)

Example stuck claim on Sepolia: 0x3b5cc63dab45e00a249fb4f4af35de20f21a563a1e5dfc3e05425bb4f6ce2a05 — 5.16 FEE stranded on split 0x75592d3372aE11212e1dd47797B84797DE6Ee98C.

Fix

• Add getFeeAsset to the frontend Rollup ABI
• New useFeeAssetTokenDetails() hook — resolves the reward token from the canonical rollup's getFeeAsset()
• Swap it in for useStakingAssetTokenDetails() in every reward claim/read path: ClaimDelegationRewardsButton, ClaimAllDelegationRewardsButton, ClaimAllRewardsModal, ClaimDelegationRewardsModal, ClaimSelfStakeRewardsModal, useAggregatedStakingData, useMultipleStakeWithProviderRewards, useTotalSplitRewards, OperatorPage

Staking/deposit flows are untouched — they correctly keep using the staking asset.

Notes

• No behavior change on mainnet (both hooks resolve to the same token there)
• Assumes all rollup versions share one fee asset (token is read from the canonical rollup only); if an old rollup version ever used a different fee asset its claims would need a per-rollup token, which the current single-token distribute/withdraw pipeline doesn't model anyway