feat: remove isRewardClaimable

[LHerskind]

Summary

Remove the reward-claimability lock from l1-contracts.

Reward claims no longer depend on a governance-controlled flag or an unlock timestamp. Claims now succeed or fail only based on the existing reward/accounting rules, such as whether rewards exist and whether prover claims are past the proof deadline.

What Changed

• Removed isRewardsClaimable and earliestRewardsClaimableTimestamp from reward storage.
• Removed the related ABI/config surface:
  • getters
  • setter
  • event
  • errors
  • rollup forwarding methods
• Removed reward-claimability checks from:
  • claimSequencerRewards
  • claimProverRewards
  • FlushRewarder.claimRewards
• Removed deploy/test config plumbing for the unlock timestamp.
• Rewrote the affected tests to cover the simplified behavior directly.
• Updated the current operator docs for claiming rewards.

[Maddiaa0]

simply lovely