feat(api): integrate EC finality calculator into v2 API and Eth RPC

CHANGELOG.md

@@ -15,7 +15,8 @@
 
 ## ⭐ New Features
 
-- feat(shed): add `lotus-shed finality-calculator` for EC finality probability computation per [FRC-0089](https://github.com/filecoin-project/FIPs/blob/master/FRCs/frc-0089.md) ([filecoin-project/lotus#12093](https://github.com/filecoin-project/lotus/pull/12093))
+- feat(api): integrate [FRC-0089](https://github.com/filecoin-project/FIPs/blob/master/FRCs/frc-0089.md) EC finality calculator into v2 API and Eth RPC, so `"finalized"` and `"safe"` tags reflect actual chain health (~20-30 epochs) rather than worst-case static 900-epoch fallback. Adds `ChainGetTipSetFinalityStatus` v2 endpoint for finality diagnostics. ([filecoin-project/lotus#13547](https://github.com/filecoin-project/lotus/pull/13547))
+- feat(shed): add `lotus-shed finality-calculator` for EC finality probability computation per FRC-0089 ([filecoin-project/lotus#12093](https://github.com/filecoin-project/lotus/pull/12093))
 
 ## 👌 Improvements
 - fix(gateway): return `ErrFilterNotFound` error instead of empty result for unknown filter IDs in `EthGetFilterLogs` ([filecoin-project/lotus#13519](https://github.com/filecoin-project/lotus/pull/13519))

api/docgen/docgen.go

@@ -481,6 +481,13 @@ func init() {
 		Input: ecchain,
 	})
 	addExample(types.TipSetSelectors.Finalized)
+	addExample(&types.FinalityStatus{
+		ECFinalityThresholdDepth: 30,
+		ECFinalizedTipSet:        &ts,
+		F3FinalizedTipSet:        &ts,
+		FinalizedTipSet:          &ts,
+		Head:                     &ts,
+	})
 }
 
 func GetAPIType(name, pkg string) (i interface{}, t reflect.Type, permStruct []reflect.Type) {

api/v2api/full.go

@@ -65,6 +65,16 @@ type FullNode interface {
 	//
 	ChainGetTipSet(context.Context, types.TipSetSelector) (*types.TipSet, error) //perm:read
 
+	// ChainGetTipSetFinalityStatus returns a breakdown of how the node is
+	// currently determining finality. The result includes the EC probabilistic
+	// finality depth (based on observed chain health), the F3-finalized tipset
+	// (if available), and the overall finalized tipset the node is using.
+	//
+	// Useful for monitoring chain health and diagnosing finality lag.
+	//
+	// Experimental: This API is experimental and may change without notice.
+	ChainGetTipSetFinalityStatus(context.Context) (*types.FinalityStatus, error) //perm:read
+
 	// MethodGroup: State
 	// The State method group contains methods for interacting with the Filecoin
 	// blockchain state, including actor information, addresses, and chain data.

api/v2api/gateway.go

@@ -18,6 +18,7 @@ var _ FullNode = (Gateway)(nil)
 
 type Gateway interface {
 	ChainGetTipSet(context.Context, types.TipSetSelector) (*types.TipSet, error)
+	ChainGetTipSetFinalityStatus(context.Context) (*types.FinalityStatus, error)
 	StateGetActor(context.Context, address.Address, types.TipSetSelector) (*types.Actor, error)
 	StateGetID(context.Context, address.Address, types.TipSetSelector) (*address.Address, error)
 	EthAddressToFilecoinAddress(ctx context.Context, ethAddress ethtypes.EthAddress) (address.Address, error)