Validate Hero Name must be longer than 30 characters

[danielmackay]

Description

The CreateHero endpoint should reject requests where the hero's Name is 30 characters or fewer. Currently CreateHeroRequestValidator only enforces .NotEmpty() on Name.

Acceptance Criteria

• CreateHeroRequestValidator rejects Name with length <= 30
• Validation message clearly states the minimum length requirement
• Unit/integration test covers boundary cases (30 chars = invalid, 31 chars = valid, empty = invalid)

Relevant code

• src/WebApi/Features/Heroes/CreateHero/CreateHeroEndpoint.cs:42 — current RuleFor(v => v.Name)