fix(zetaclient): backport respect DisableTssBlockScan in Bitcoin observer

zetaclient/chains/bitcoin/observer/inbound.go

@@ -28,6 +28,14 @@ func (ob *Observer) ObserveInbound(ctx context.Context) error {
 		return err
 	}
 
+	// Bitcoin's only inbound mechanism is direct transfers to the TSS address.
+	// When DisableTssBlockScan is true, skip all inbound scanning so new deposits
+	// are not observed (outbound/withdrawal processing is unaffected).
+	if ob.ChainParams().DisableTssBlockScan {
+		ob.Logger().Sampled.Info().Msg("skip inbound observation: DisableTssBlockScan is true")
+		return nil
+	}
+
 	// get fee rate multiplier
 	feeRateMultiplier, err := ob.ChainParams().GasPriceMultiplier.Float64()
 	if err != nil {

zetaclient/chains/bitcoin/observer/inbound_test.go

@@ -146,6 +146,43 @@ func TestAvgFeeRateBlock828440Errors(t *testing.T) {
 	})
 }
 
+func Test_ObserveInbound_DisableTssBlockScan(t *testing.T) {
+	chain := chains.BitcoinMainnet
+	ob := newTestSuite(t, chain)
+
+	// flip the chain param to disable inbound scanning
+	chainParams := ob.ChainParams()
+	chainParams.DisableTssBlockScan = true
+	ob.SetChainParams(chainParams)
+
+	// ObserveInbound should return early without scanning any block.
+	// We intentionally do NOT mock GetBlockHash/GetBlockVerbose — if scanning
+	// were attempted, the mock client would fail the test on unexpected calls.
+	err := ob.ObserveInbound(ob.ctx)
+	require.NoError(t, err)
+}
+
+func Test_ObserveInboundTrackers_DisableTssBlockScan(t *testing.T) {
+	chain := chains.BitcoinMainnet
+	ob := newTestSuite(t, chain)
+
+	chainParams := ob.ChainParams()
+	chainParams.DisableTssBlockScan = true
+	ob.SetChainParams(chainParams)
+
+	// Even with trackers present, observeInboundTrackers should return early.
+	// We intentionally do NOT mock GetRawTransactionVerbose/GetBlockVerbose —
+	// if processing were attempted, the mock client would fail on unexpected calls.
+	trackers := []crosschaintypes.InboundTracker{
+		{ChainId: chain.ChainId, TxHash: "abc"},
+	}
+	err := ob.observeInboundTrackers(ob.ctx, trackers, false)
+	require.NoError(t, err)
+
+	err = ob.observeInboundTrackers(ob.ctx, trackers, true)
+	require.NoError(t, err)
+}
+
 func Test_GetInboundVoteFromBtcEvent(t *testing.T) {
 	r := sample.Rand()
 

zetaclient/chains/bitcoin/observer/inbound_tracker.go

@@ -43,6 +43,18 @@ func (ob *Observer) observeInboundTrackers(
 	trackers []types.InboundTracker,
 	isInternal bool,
 ) error {
+	// Bitcoin's only inbound mechanism is direct transfers to the TSS address.
+	// When DisableTssBlockScan is true, skip inbound tracker processing so new
+	// deposits referenced by external or internal trackers are not voted on
+	// (outbound/withdrawal processing is unaffected).
+	if ob.ChainParams().DisableTssBlockScan {
+		ob.Logger().Sampled.Info().
+			Bool("is_internal", isInternal).
+			Int("tracker_count", len(trackers)).
+			Msg("skip inbound tracker processing: DisableTssBlockScan is true")
+		return nil
+	}
+
 	// take at most MaxInternalTrackersPerScan for each scan
 	if len(trackers) > config.MaxInboundTrackersPerScan {
 		trackers = trackers[:config.MaxInboundTrackersPerScan]