feat: migrate from msgpack to protobuf (handler-base v1.0.0)

- Replace msgpack.Marshal with proto.Marshal
- Update field names to proto convention (SessionId, SpeakerId)
- Cast Sequence to int32 for proto compatibility

go.mod

@@ -3,9 +3,9 @@ module git.daviestechlabs.io/daviestechlabs/stt-module
 go 1.25.1
 
 require (
-	git.daviestechlabs.io/daviestechlabs/handler-base v0.1.5
+	git.daviestechlabs.io/daviestechlabs/handler-base v1.0.0
 	github.com/nats-io/nats.go v1.48.0
-	github.com/vmihailenco/msgpack/v5 v5.4.1
+	google.golang.org/protobuf v1.36.11
 )
 
 require (
@@ -19,7 +19,6 @@ require (
 	github.com/klauspost/compress v1.18.0 // indirect
 	github.com/nats-io/nkeys v0.4.11 // indirect
 	github.com/nats-io/nuid v1.0.1 // indirect
-	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
 	go.opentelemetry.io/otel v1.40.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v1.40.0 // indirect
@@ -37,5 +36,4 @@ require (
 	google.golang.org/genproto/googleapis/api v0.0.0-20260128011058-8636f8732409 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20260128011058-8636f8732409 // indirect
 	google.golang.org/grpc v1.78.0 // indirect
-	google.golang.org/protobuf v1.36.11 // indirect
 )