fix: enhance graceful shutdown (#66)

* enhance graceful shutdown

* wrap with lock

* apply comments

feat: use real time as block time (#65)

* use local time as block time instead of previous block commit median

* add validation

fix: wait until all sequencing engine processors finish (#64)

feat: stop sequencing engine when we detect app upgrade (#62)

* stop sequencing engine when we detect app upgrade

* use error log

* Update sequencing/engine/handlers.go

Co-authored-by: Copilot <[email protected]>

* naming

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Co-authored-by: Copilot <[email protected]>

fix to use latest state height if store height is zero (#61)

fix: use pre-set proposer (#59)

* use pre-set proposer

* update proposer if not set

fix: filtermap (#58)

* prevent loading head from height 0, not from base height

* add test cases

* enhance zero matchers

* Update state/filtermaps/matcher.go

Co-authored-by: Copilot <[email protected]>

* fix

* apply comment

* remove unnecessary code

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Co-authored-by: Copilot <[email protected]>

fix(light): determine proposer from block header in validator set (#57)