Allow additional table and wrapper CSS classes

[Zhortein]

Objective

Allow developers to add custom CSS classes to the rendered table and wrapper.

Context

Applications may need project-specific classes for spacing, borders, themes, responsive behavior or custom styles.

Scope

• Add runtime options for additional CSS classes.
• Support at least:
  • root wrapper class;
  • table wrapper class;
  • table class.
• Preserve existing classes.
• Avoid overwriting Bootstrap defaults.
• Add tests.
• Update documentation.

Out of scope

• Full CSS asset system.
• Theme registry.
• Tailwind support.

Constraints

• Runtime options must be simple.
• Developer-provided classes are appended, not replacing core classes unless explicitly designed.
• TwigCS and PHPStan must pass.

Acceptance criteria

• Additional root wrapper classes can be rendered.
• Additional table wrapper classes can be rendered.
• Additional table classes can be rendered.
• Defaults remain unchanged.
• Tests cover class merging.
• Documentation is updated.
• QA passes.