implement grpc comms

[marcello33]

Related to:

• full raw header and additional methods for bor polyproto#11
• consensus/bor, internal/cli: full grpc implementation bor#2194
• app, helper, x/bor: full grpc implementation heimdall-v2#576

These changes have been used to test the feature locally on a kurtosis devnet

[leovct]

lgtm but heimdall is not able to start in CI?

2026/04/24 07:50:49 unable to unmarshall config Error decoding failed due to the following error(s):
'custom' has invalid keys: main_chain_gas_fee_cap, main_chain_gas_tip_cap

[marcello33]

lgtm but heimdall is not able to start in CI?

2026/04/24 07:50:49 unable to unmarshall config Error decoding failed due to the following error(s):

'custom' has invalid keys: main_chain_gas_fee_cap, main_chain_gas_tip_cap

Yeah @leovct
It's because we use the latest released version here which doesn't have those flags, whilst develop does. It should be super safe to merge (I tested this locally many times)