Implement Album management with full CRUD operations

This commit introduces comprehensive Album entity management following
the established repository pattern used for other entities like AlbumType
and SamplingRate. The Album entity includes relationships with AlbumType
and AlbumArt entities.

Key components implemented:

Model Layer:
- Album entity with complete field set:
  * Basic fields: id, name, year, numberOfDiscs, code, isCompilation
  * Foreign key relationships: AlbumType and AlbumArt (ManyToOne)
  * Audit timestamps: createdAt, updatedAt with JPA lifecycle hooks
- JPA annotations with @PrePersist and @PreUpdate for automatic timestamps
- Complete getters and setters

Repository Layer:
- AlbumRepository with EntityManager-based operations
- Full transaction management with proper rollback handling
- Methods: save, findAll, findById, update, deleteById

Service Layer:
- AlbumService with business logic and validation
- Constructor injection of AlbumRepository, AlbumTypeRepository, AlbumArtRepository
- Relationship handling: validates and sets AlbumType and AlbumArt entities
- Input validation for null/empty name field
- ID validation for all operations requiring entity lookup
- Comprehensive logging using Log4j2

Mapper Layer:
- AlbumMapper for bidirectional entity/protobuf conversion
- Timestamp conversion between LocalDateTime and epoch milliseconds
- Foreign key mapping for AlbumType and AlbumArt relationships
- Null safety checks and validation
- Proper handling of optional fields

Action Handlers:
- CreateAlbumHandler (album.create)
- GetAlbumHandler (album.getAll)
- GetAlbumByIdHandler (album.getById)
- UpdateAlbumHandler (album.update)
- DeleteAlbumHandler (album.delete)
- HTTP status code handling: 200 (success), 400 (validation),
  404 (not found), 500 (server error)
- Handles optional fields with proper default value checks

Protocol Buffers:
- Fixed proto definition with correct Album fields
- CreateAlbumRequest and UpdateAlbumRequest with all entity fields
- All CRUD message definitions (Create, Get, GetById, Update, Delete)
- Support for foreign keys and timestamps

Service Registration:
- AlbumRepository initialized with EntityManagerFactory
- AlbumService registered with ServiceLocator with required dependencies
- Ensures all Album action handlers can resolve dependencies

The implementation follows best practices with proper error handling,
logging, validation, relationship management, and consistency with
existing codebase patterns.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/main/proto/album.proto

@@ -0,0 +1,77 @@
+syntax = "proto3";
+
+option java_package = "com.mediamanager.protocol.messages";
+option java_outer_classname = "AlbumMessages";
+
+package mediamanager.messages;
+
+message Album {
+  int32 id = 1;
+  string name = 2;
+  int32 year = 3;
+  int32 number_of_discs = 4;
+  string code = 5;
+  bool is_compilation = 6;
+
+
+  int32 fk_albumtype_id = 7;
+  int32 fk_albumart_id = 8;
+
+
+  int64 created_at = 9;
+  int64 updated_at = 10;
+}
+
+message CreateAlbumRequest {
+  string name = 1;
+  int32 year = 2;
+  int32 number_of_discs = 3;
+  string code = 4;
+  bool is_compilation = 5;
+  int32 fk_albumtype_id = 6;
+  int32 fk_albumart_id = 7;
+}
+
+message CreateAlbumResponse {
+  Album album = 1;
+}
+
+message GetAlbumsRequest {
+
+}
+
+message GetAlbumsResponse {
+  repeated Album albums = 1;
+}
+
+message GetAlbumByIdRequest {
+  int32 id = 1;
+}
+
+message GetAlbumByIdResponse {
+  Album album = 1;
+}
+
+message UpdateAlbumRequest {
+  int32 id = 1;
+  string name = 2;
+  int32 year = 3;
+  int32 number_of_discs = 4;
+  string code = 5;
+  bool is_compilation = 6;
+  int32 fk_albumtype_id = 7;
+  int32 fk_albumart_id = 8;
+}
+
+message UpdateAlbumResponse {
+  Album album = 1;
+}
+
+message DeleteAlbumRequest {
+  int32 id = 1;
+}
+
+message DeleteAlbumResponse {
+  bool success = 1;
+  string message = 2;
+}