[Docs] ADR-MF-02 — Neutral Workflow / Claims (design gate for PR-2) #159

Problem

Work management is currently GitHub-specific in terminology and policy. The
Multi-Forge architecture freezes a provider-neutral "Work Authority" model and a
claim protocol with durable local journaling, but that decision cluster exists only
in the external architecture document. It must be recorded as an accepted ADR
before the workflow/claims implementation (PR-2) starts.

Source: Multi-Forge v1.3.2-final §17, §45–54 (ADR-MF-02).

Expected outcome

An accepted ADR (decisions only) that freezes:

• Terminology: Work Authority, WorkItem, ChangeRequest, WorkAuthorityRef.
• Ownership: the skill/harness owns remote facts; ainative/forge.py owns a pure
  local resolver; observed candidates are diagnostic only.
• Claim identity: principal <provider>:principal:<stable-provider-id>; event
  <provider>:<event-kind>:<stable-event-id>; V1 event kinds comment, note,
  assignment; UTC timestamps; winner ordering
  (created_at_utc, canonical_event_identifier).
• ClaimAttempt journal under .ai-native/state/claim-attempts/: local, durable,
  non-authoritative, non-Verified; PENDING attempt written durably before the
  remote POST.
• Outcomes: CONFIRMED, LOST, CONFLICT, UNCERTAIN, ABANDONED; refusal
  codes CLAIM_CONFLICT, CLAIM_UNCERTAIN, CLAIM_JOURNAL_UNAVAILABLE;
  ABANDONED is an explicit operator transition; a new claim is allowed only after
  explicit abandonment; no automatic re-POST of an uncertain attempt.
• No leases, no heartbeat, no age-based expiry, no remote API clients.

Acceptance criteria

• ADR written in docs/adr/ following the repository series format; decisions
  only; incorporates the frozen points above.
• The local resolver contract is stated as pure (no network, no credential
  lookup, no writes, no provider API calls, no push authorization).
• Journal-before-POST and fail-closed semantics for corrupted/unwritable
  journals are explicit.
• Rejected alternatives recorded (leases/heartbeats, retry-on-uncertain,
  remote claim service, provider API clients in the neutral layer).
• Accepted by the maintainer before PR-2 begins.
• Issue [Feature] Add a designed stale-claim expiration for multi-agent issue claims #33 (stale claim lifecycle) and [MV-19] Managed Git guard hook file and authenticated local IPC #120 (managed Git guard / push
  mediation) remain independent and unchanged.

Out of scope

• Implementing the workflow neutralization or the resolver (PR-2).
• GitLab/GitHub WorkItem API clients (explicitly excluded architecture-wide).
• Leases, heartbeats, expiration services.

Context

• docs/GITHUB-WORKFLOW.md — current GitHub-specific policy.
• skills/issue-to-implementation/ — current claim-resolution implementation.
• Blocks PR-2 (with PR-1 green).

Dependencies

• None. Blocks PR-2 ([Feature] Neutral workflow, Work Authority and claim journal (PR-2) #163).