feat(domain): refine domain models with enums, enum serialization, and embedded metrics (SPEC-0002)

feat(domain): implement domain models specification and code (SPEC-0002)

refactor(config): finalize and freeze SPEC-0001 Configuration Manager

feat(config): implement Configuration Manager based on SPEC-0001

docs(design): add DESIGN-0001 Configuration Manager

docs: refine design template and finalise M0.0 freeze

docs: establish design template, vocabulary rules, and freeze M0.0

docs: establish engineering principles and draft foundation RFC

docs: establish SPEC template and mandate SPEC-driven workflow

docs: finalize architecture review and establish mental model

docs: architecture review revision 1

docs: establish professional project documentation skeleton and CLAUDE.md

feat: initialize repository with documentation skeleton and project guidelines