* op-program: Implement deposit-only block receipt hint

* op-program: Reflective program for block execution

* op-program: Hook new hint route to the L2 oracle

* op-program: Fix prefetch hint for L2BlockData

* op-program: Abstract program execution in prefetcher

* op-program: Add chainID to l2-block-data hint

* Derive block succeeding the agreed block

* fix validation on client.Main

* refactor L2Source interface

* uint8 chainID; fix TODOs

* add test for block exec cache hit

* remove useless comment