Reward claiming fails for Berachain RewardVaults due to incorrect interface

Bera_Module is designed to stake the strategy's position into Berachain RewardVaults and periodically claim accrued BGT rewards. The claim path uses an interface for RewardVault whose function signature does not match the actual deployed contract on Berachain.

Because the function selector encoded into the calldata does not exist on the target, every call to claim BGT rewards reverts with the standard "function does not exist" failure (or unwinds further upstream in the strategy fallback).

The consequence is that BGT continues to accrue inside the RewardVault for the strategy's stake, but the strategy can never extract those rewards. The position keeps growing in unclaimed rewards while remaining inaccessible.

• All BGT rewards earned from Berachain RewardVault staking are stranded.
• The strategy cannot use BGT to boost validators or compound back into the position.
• Yield reported to depositors silently undercounts the actual BGT entitlement.
• Existing fix paths (e.g. closing and reopening the position) do not return the unclaimed rewards because they accrue at the RewardVault, not the staker.

Replace the interface definition with the actual RewardVault interface published in the Berachain documentation (the function name, argument types, and return type must all match exactly). After the fix, add an integration test that stakes, advances time, and asserts that a non-zero amount of BGT lands in the strategy after claim.

D2: Fixed.

Cyfrin: Verified.