Disambiguate duplicate BookcaseMapper across infrastructure and web layers

[leodvincci]

Context

From the Naming Is a Feature Audit (PR #342).

Problem

Two classes named BookcaseMapper exist in different layers:

• Infrastructure: bookcase.infrastructure.persistence.mapping.BookcaseMapper — maps Entity ↔ Domain
• Web: web.controllers.stacks.bookcase.BookcaseMapper — maps Domain → DTO

rg "class BookcaseMapper" returns two hits. Neither name reveals its layer or what it maps between.

Renames

Current	Proposed	Rationale
infrastructure...BookcaseMapper	BookcaseEntityMapper	Clarifies it maps entities
web...BookcaseMapper	BookcaseDtoMapper	Clarifies it maps DTOs

Verification

mvn test — static method call sites update via IDE rename.

Risk

Medium. All BookcaseMapper::toDomain and BookcaseMapper::toDTO static calls must be updated.