deps: bump consensus v1.23.2 + threshold v1.6.7 + ZAP-native rpcdb

* consensus v1.23.2 — pulls threshold v1.6.7 with the LSS-Pulsar
  adapter (PulsarConfig, DynamicResharePulsar) needed by the epoch
  manager's resharing path.
* New proto/zap/rpcdb package — pure-Go wire types for the database
  RPC, no protobuf. Mirrors the proto/zap/{vm,p2p,sync,platformvm}
  pattern.
* New proto/rpcdb/rpcdb_zap.go (build tag !grpc) — full ZAP-native
  DatabaseClient + DatabaseServer + Register hook, implements
  database.Database against any Transport. The host's underlying DB
  is luxfi/database (zapdb in production); the protocol shape is
  identical regardless of which engine the host runs.
* Renamed the existing rpcdb.go to rpcdb_grpc.go so the two
  variants are mutually exclusive: build with no tag (ZAP default)
  or with `-tags=grpc` (protobuf path), never both.

examples/multi-network/multi-network-poc.go: drop duplicate-key map
entry where Q-Chain was illustrated as a separate network — Q-Chain
shares the primary network ID per LP-134, see comments on
MainnetID entry.

Net effect: full default build is ZAP-only PQ-secure-channel-aware,
RPC over a Z-Wing-encrypted ZAP transport, no gRPC/protobuf in the
critical path.

examples/multi-network/multi-network-poc.go

@@ -63,14 +63,12 @@ func NewMultiNetworkNode() *MultiNetworkNode {
 				ChainID:     "2ebCneCbwthjQ1rYT41nhd7M76Hc6YmosMAQrTFhBq8qeqh6tt",
 				Active:      true,
 			},
-			constants.QChainMainnetID: { // 36963 - Q-Chain
-				NetworkID:   constants.QChainMainnetID,
-				NetworkName: "Hanzo Network (Q-Chain)",
-				RPCPort:     3690,
-				Validators:  5,
-				ChainID:     "2TtHFqEAAJ6b33dromYMqfgavGPF3iCpdG3hwNMiart2aB5QHi",
-				Active:      true,
-			},
+			// Q-Chain is part of the primary network (mainnet ID 1)
+			// and no longer has a separate network ID — see the
+			// MainnetID entry above. The Q-Chain blockchain ID lives
+			// in luxfi/constants.QChainID; consumers can read it from
+			// the primary-network entry's chain registry rather than
+			// from a duplicate top-level map entry here.
 		},
 	}
 }