feat: migrate to typed messages, drop base64

- Decode TTSRequest via natsutil.Decode[messages.TTSRequest]
- Stream audio as raw bytes via messages.TTSAudioChunk (no base64)
- Non-stream response uses messages.TTSFullResponse
- Status updates use messages.TTSStatus
- Voice list/refresh use messages.TTSVoiceListResponse/TTSVoiceRefreshResponse
- Registry returns []messages.TTSVoiceInfo (not []map[string]any)
- Remove strVal/boolVal helpers
- Add .dockerignore, GOAMD64=v3 in Dockerfile
- Update tests for typed structs (13 tests pass)

e2e_test.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"bytes"
-	"encoding/base64"
 	"encoding/json"
 	"io"
 	"net/http"
@@ -11,6 +10,9 @@ import (
 	"path/filepath"
 	"strconv"
 	"testing"
+
+	"git.daviestechlabs.io/daviestechlabs/handler-base/messages"
+	"github.com/vmihailenco/msgpack/v5"
 )
 
 // ────────────────────────────────────────────────────────────────────────────
@@ -63,26 +65,29 @@ func TestSynthesisE2E_StreamChunks(t *testing.T) {
 		chunkIdx := i / chunkSize
 		isLast := end >= len(audioBytes)
 
-		// Verify chunk message shape
-		msg := map[string]any{
-			"session_id":   "test-session",
-			"chunk_index":  chunkIdx,
-			"total_chunks": totalChunks,
-			"audio_b64":    base64.StdEncoding.EncodeToString(chunk),
-			"is_last":      isLast,
-			"sample_rate":  24000,
+		// Verify typed chunk struct
+		msg := messages.TTSAudioChunk{
+			SessionID:   "test-session",
+			ChunkIndex:  chunkIdx,
+			TotalChunks: totalChunks,
+			Audio:       chunk,
+			IsLast:      isLast,
+			SampleRate:  24000,
 		}
 
-		// Round-trip through JSON
-		data, _ := json.Marshal(msg)
-		var decoded map[string]any
-		json.Unmarshal(data, &decoded)
+		// Round-trip through msgpack
+		data, _ := msgpack.Marshal(&msg)
+		var decoded messages.TTSAudioChunk
+		msgpack.Unmarshal(data, &decoded)
 
-		if decoded["session_id"] != "test-session" {
-			t.Errorf("chunk %d: session = %v", chunkIdx, decoded["session_id"])
+		if decoded.SessionID != "test-session" {
+			t.Errorf("chunk %d: session = %v", chunkIdx, decoded.SessionID)
 		}
-		if decoded["is_last"] != isLast {
-			t.Errorf("chunk %d: is_last = %v, want %v", chunkIdx, decoded["is_last"], isLast)
+		if decoded.IsLast != isLast {
+			t.Errorf("chunk %d: is_last = %v, want %v", chunkIdx, decoded.IsLast, isLast)
+		}
+		if len(decoded.Audio) != len(chunk) {
+			t.Errorf("chunk %d: audio len = %d, want %d", chunkIdx, len(decoded.Audio), len(chunk))
 		}
 	}
 }
@@ -260,8 +265,14 @@ func BenchmarkAudioChunking(b *testing.B) {
 				end = len(audioBytes)
 			}
 			chunk := audioBytes[i:end]
-			_ = base64.StdEncoding.EncodeToString(chunk)
-			_ = totalChunks
+			msg := &messages.TTSAudioChunk{
+				SessionID:   "bench",
+				ChunkIndex:  i / chunkSize,
+				TotalChunks: totalChunks,
+				Audio:       chunk,
+				SampleRate:  24000,
+			}
+			msgpack.Marshal(msg)
 		}
 	}
 }