feat: implement F3 list participants API (#12608)

* Implement F3 list participants API

Implement Lotus API to list the current miner IDs that are
participating.

* Include lease information to list participants API

Also return start and validity terms of the list participants API.

CHANGELOG.md

@@ -9,6 +9,7 @@
 - Fix hotloop in F3 pariticpation API ([filecoin-project/lotus#12575](https://github.com/filecoin-project/lotus/pull/12575))
 - `lotus chain head` now supports a `--height` flag to print just the epoch number of the current chain head ([filecoin-project/lotus#12609](https://github.com/filecoin-project/lotus/pull/12609))
 - `lotus-shed indexes inspect-indexes` now performs a comprehensive comparison of the event index data for each message by comparing the AMT root CID from the message receipt with the root of a reconstructed AMT. Previously `inspect-indexes` simply compared event counts, comparing AMT roots confirms all the event data is byte-perfect. ([filecoin-project/lotus#12570](https://github.com/filecoin-project/lotus/pull/12570))
+- Expose APIs to list the miner IDs that are currently participating in F3 via node. ([filecoin-project/lotus#12608](https://github.com/filecoin-project/lotus/pull/12608))
 
 ## Bug Fixes
 - Fix a bug in the `lotus-shed indexes backfill-events` command that may result in either duplicate events being backfilled where there are existing events (such an operation *should* be idempotent) or events erroneously having duplicate `logIndex` values when queried via ETH APIs. ([filecoin-project/lotus#12567](https://github.com/filecoin-project/lotus/pull/12567))

api/api_full.go

@@ -966,6 +966,8 @@ type FullNode interface {
 	F3IsRunning(ctx context.Context) (bool, error) //perm:read
 	// F3GetProgress returns the progress of the current F3 instance in terms of instance ID, round and phase.
 	F3GetProgress(ctx context.Context) (gpbft.Instant, error) //perm:read
+	// F3ListParticipants returns the list of miners that are currently participating in F3 via this node.
+	F3ListParticipants(ctx context.Context) ([]F3Participant, error) //perm:read
 }
 
 // F3ParticipationTicket represents a ticket that authorizes a miner to
@@ -993,6 +995,19 @@ func (l *F3ParticipationLease) ToInstance() uint64 {
 	return l.FromInstance + l.ValidityTerm
 }
 
+// F3Participant captures information about the miners that are currently
+// participating in F3, along with the number of instances for which their lease
+// is valid.
+type F3Participant struct {
+	// MinerID is the actor ID of the miner that is
+	MinerID uint64
+	// FromInstance specifies the instance ID from which this lease is valid.
+	FromInstance uint64
+	// ValidityTerm specifies the number of instances for which the lease remains
+	// valid from the FromInstance.
+	ValidityTerm uint64
+}
+
 // EthSubscriber is the reverse interface to the client, called after EthSubscribe
 type EthSubscriber interface {
 	// note: the parameter is ethtypes.EthSubscriptionResponse serialized as json object