Bootstrap initial enum component implementation

[coisa]

Summary

Bootstrap the initial fast-forward/enum component with ergonomic enum helpers, reusable common enums, and workflow/state-machine utilities.

Initial scope

• Backed and unit enum helpers through Helper\\EnumHelper
• Traits for names, values, maps, lookups, labels, descriptions, and comparisons
• Enum-driven state machine helpers with transition validation
• Reusable common enums for environment, priority, severity, weekday, and month
• Test coverage and package documentation
• Consumer tooling alignment with fast-forward/dev-tools

Follow-up items already identified

• Review HasLabel default semantics for long-term API shape
• Revisit dev-tools sync expectations for .gitignore
• Add docs skeleton so dev-tools reports flow is fully green
• Tighten PHPUnit coverage metadata attributes for traits/interfaces under dev-tools coverage mode

Notes

This issue tracks the initial implementation wave for the new repository.