Describe the feature

currently we clear the tracked flashblock:

what we should be doing is also take the local height into account and try caching like 3 blocks, e.g. head is N, and flashblocks are already ticking and N + X
then we should cache the flashblocks if distance X - N is within, let's do 3 blocks for now.

and then pick the proper block when we execute:

this requires a smol redesign because then the local header guides flashblock selection
in case local N + 1 is X - 2 for example.

TODO

• introduce basic cache (like a vecqueue)
• change selection logic so that local head is used when selecting the flashblock for building

Additional context

No response