feat: migrate to typed messages, drop base64

- Switch OnMessage → OnTypedMessage with natsutil.Decode[messages.ChatRequest]
- Return *messages.ChatResponse / *messages.ChatStreamChunk (not map[string]any)
- Audio as raw []byte in msgpack (25% wire savings vs base64)
- Remove strVal/boolVal/intVal helpers
- Add .dockerignore, GOAMD64=v3 in Dockerfile
- Update tests for typed structs (9 tests pass)

e2e_test.go

@@ -9,6 +9,8 @@ import (
 "time"
 
 "git.daviestechlabs.io/daviestechlabs/handler-base/clients"
+"git.daviestechlabs.io/daviestechlabs/handler-base/messages"
+"github.com/vmihailenco/msgpack/v5"
 )
 
 // ────────────────────────────────────────────────────────────────────────────
@@ -161,39 +163,38 @@ t.Error("expected timeout error")
 }
 }
 
-func TestChatPipeline_RequestBuilding(t *testing.T) {
-// Test the map construction logic from main.go's OnMessage.
-data := map[string]any{
-"request_id":       "req-e2e-001",
-"user_id":          "user-1",
-"message":          "hello",
-"premium":          true,
-"enable_rag":       false,
-"enable_streaming": false,
-"system_prompt":    "Be brief.",
-}
+func TestChatPipeline_TypedDecoding(t *testing.T) {
+	// Verify typed struct decoding from msgpack (same path as OnTypedMessage).
+	raw := map[string]any{
+		"request_id":       "req-e2e-001",
+		"user_id":          "user-1",
+		"message":          "hello",
+		"premium":          true,
+		"enable_rag":       false,
+		"enable_streaming": false,
+		"system_prompt":    "Be brief.",
+	}
+	data, _ := msgpack.Marshal(raw)
 
-requestID := strVal(data, "request_id", "unknown")
-userID := strVal(data, "user_id", "unknown")
-query := strVal(data, "message", "")
-premium := boolVal(data, "premium", false)
-enableRAG := boolVal(data, "enable_rag", premium)
-systemPrompt := strVal(data, "system_prompt", "")
+	var req messages.ChatRequest
+	if err := msgpack.Unmarshal(data, &req); err != nil {
+		t.Fatal(err)
+	}
 
-if requestID != "req-e2e-001" {
-t.Errorf("requestID = %q", requestID)
-}
-if userID != "user-1" {
-t.Errorf("userID = %q", userID)
-}
-if query != "hello" {
-t.Errorf("query = %q", query)
-}
-if enableRAG {
-t.Error("enable_rag=false should override premium=true")
-}
-if systemPrompt != "Be brief." {
-t.Errorf("systemPrompt = %q", systemPrompt)
+	if req.RequestID != "req-e2e-001" {
+		t.Errorf("RequestID = %q", req.RequestID)
+	}
+	if req.UserID != "user-1" {
+		t.Errorf("UserID = %q", req.UserID)
+	}
+	if req.EffectiveQuery() != "hello" {
+		t.Errorf("query = %q", req.EffectiveQuery())
+	}
+	if req.EnableRAG {
+		t.Error("EnableRAG should be false")
+	}
+	if req.SystemPrompt != "Be brief." {
+		t.Errorf("SystemPrompt = %q", req.SystemPrompt)
 }
 }