Implement Composer Management with CRUD Operations

- Add `Composer` entity with JPA annotations and database mapping.
- Create repository, service, and delegate handlers for Composer CRUD operations: `create_composer`, `get_composers`, `get_composer_by_id`, `update_composer`, `delete_composer`.
- Introduce Protobuf definitions for Composer messages.
- Register Composer service and handlers in `DelegateActionManager`.
- Add `ComposerMapper` to map between Protobuf and entity models.
- Enhance error handling and logging for Composer operations.

src/main/proto/composer.proto

@@ -0,0 +1,51 @@
+syntax = "proto3";
+
+option java_package = "com.mediamanager.protocol.messages";
+option java_outer_classname = "ComposerMessages";
+
+package mediamanager.messages;
+
+message Composer {
+  int32 id =1;
+  string name =2;
+}
+
+message CreateComposerRequest{
+  string name =1;
+}
+
+message CreateComposerResponse{
+  Composer composer = 1;
+}
+
+message GetComposersRequest{}
+
+message GetComposersResponse{
+  repeated Composer composers = 1;
+}
+
+message GetComposerByIdRequest{
+  int32 id =1;
+}
+
+message GetComposerByIdResponse{
+  Composer composer =1;
+}
+
+message UpdateComposerRequest{
+  int32 id = 1;
+  string name=2;
+}
+
+message UpdateComposerResponse{
+  Composer composer = 1;
+}
+
+message DeleteComposerRequest{
+  int32 id = 1;
+}
+
+message DeleteComposerResponse{
+  bool success = 1;
+  string message = 2;
+}