Implement Genre Management with CRUD Operations

- Add `Genre` entity with JPA annotations and database mapping.
- Create repository, service, and delegate handlers for Genre CRUD operations.
- Register handlers (`create_genre`, `get_genres`, `get_genre_by_id`, `update_genre`, `delete_genre`) in `DelegateActionManager`.
- Introduce Protobuf definitions for Genre messages.
- Update `DatabaseManager` to expose `EntityManager`.
- Enhance `DelegateActionManager` constructor to use `EntityManager` for handler initialization.

src/main/proto/genre.proto

@@ -0,0 +1,53 @@
+syntax = "proto3";
+
+option java_package = "com.mediamanager.protocol.messages";
+option java_outer_classname = "GenreMessages";
+
+package mediamanager.messages;
+
+message Genre {
+  int32 id = 1;
+  string name = 2;
+}
+
+message CreateGenreRequest {
+  string name = 1;
+}
+
+message CreateGenreResponse {
+  Genre genre = 1;
+}
+
+message GetGenresRequest {
+
+}
+
+message GetGenresResponse {
+  repeated Genre genres = 1;
+}
+
+message GetGenreByIdRequest {
+  int32 id = 1;
+}
+
+message GetGenreByIdResponse {
+  Genre genre = 1;
+}
+
+message UpdateGenreRequest {
+  int32 id = 1;
+  string name = 2;  // Novo nome
+}
+
+message UpdateGenreResponse {
+  Genre genre = 1;  // Genre atualizado
+}
+
+message DeleteGenreRequest {
+  int32 id = 1;
+}
+
+message DeleteGenreResponse {
+  bool success = 1;
+  string message = 2;
+}