docs(governance): define phase 0 identity and ownership

[back1ash]

Closes #6

Summary

• adopt SpecArgus PROOF as the Phase 0 public working identity and record the intended repository, CLI, package, and GitHub App names;
• define the Phase 0 co-maintainer role as the accountable owner, with @back1ash, @Seo-yul, and @minsubyun1 holding equal authority and existing GitHub admin permissions;
• require recorded agreement from at least two co-maintainers for material product, architecture, security, governance, and release decisions while allowing any co-maintainer to perform urgent proportionate security containment;
• designate both @Seo-yul and @minsubyun1 as corpus evidence reviewers without creating an authority tier or branch-protection approval requirement;
• document Phase 0 entry criteria, the exit-evidence trigger with no fixed calendar review date, decision outcomes, and follow-up owners/review points; and
• align CODEOWNERS, governance, contribution, branching, security, roadmap, changelog, and ADR documentation.

Role acknowledgement

This PR intentionally remains Draft and ADR 0001 remains Proposed until all three current role members explicitly acknowledge the shared responsibilities. These acknowledgements are governance records; they do not enable or add a required PR approval count.

• @back1ash - requested and accepted the equal co-maintainer model in the project planning discussion
• @Seo-yul
• @minsubyun1

After all three acknowledgements are recorded, ADR 0001 and its index must be changed from Proposed to Accepted in this PR before it is marked ready and merged.

Rationale

The repository already grants all three accounts equal admin permission. The previous single-owner wording did not match that operating model and created an unnecessary primary/fallback hierarchy. This change makes the documented authority match the existing repository permissions while preserving a clear decision rule and security escalation path.

Acceptance criteria

• The public-name decision and rationale are documented.
• Intended repository, CLI, package, and GitHub App names are recorded.
• Each ownership area is assigned to the named Phase 0 co-maintainer role.
• Backup, conflict-of-interest, quorum, and urgent-security paths are documented.
• Phase 0 entry criteria, evidence, decision authority, and review trigger are documented.
• Permitted outcomes are explicit: proceed, revise and re-evaluate, or stop.
• Unresolved naming and registration questions have named owners and review points.
• All three current role members have acknowledged the responsibilities.

Validation

• scripts/validate-repository.ps1 - passed for 24 text files with PR base/head/title inputs
• git diff --check - passed
• staged scope inspection - exactly 10 Issue decision(product): confirm public identity, ownership, and Phase 0 gate #6 files
• GitHub collaborator permission check - all three role members currently have admin

Security and compatibility impact

This is a governance and documentation change only; it does not choose a runtime, validator, schema, package manager, or hosted architecture. It clarifies private security escalation and urgent containment authority. Required approving reviews remain set to zero; required CI and resolved review conversations remain enforced.

Deferred decisions

• runtime-specific CLI and package registration in decision(repo): select runtime and repository architecture #5;
• GitHub App display-name and normalized-slug validation in spike(github): validate public fork PR Checks and trust isolation #7 and research(product): interview target maintainers and decide hosted App direction #9;
• hosted-product recommendation in research(product): interview target maintainers and decide hosted App direction #9; and
• permanent launch-name review at the Phase 0 gate.