feat(artificer): add explicit local ticket delivery

[BjRo]

Why

Refs #157. Add the local Artificer adapter for explicitly authorized recurring ticket delivery, independently of the GitHub Actions follow-up.

What changed

• Add the self-contained darrow-artificer plugin with explicit-only management, launchd scheduling, model-free eligibility/reply/PR polling, shared-lock reservations, conservative cancellation/recovery and encrypted native archives.
• Pin execution to Codex CLI 0.154.0 with persistent ChatGPT Pro login, included-usage checks, and same-parent/same-owner continuation; no API fallback or credit purchase path.
• Add a deliberate saved-grant unattended entry to ticket-to-pr without moving engineering ownership into the adapter; update paired manifests, specifications, catalog and guide fixtures.
• Add mechanical tests, explicit behavior evals and reproducible live native/launchd probes.

Verification

• bun test passed 632 tests across 56 files (2,343 assertions), with zero failures.
• bun run check:python passed across all registered packages; final bun run check:python --package plugins/automation/darrow-artificer/backend passed 130 tests, Ruff, strict mypy, 99.26% statement and 96.83% branch coverage.
• uv run --isolated --python <3.10|3.11|3.12> --frozen --group dev --project plugins/automation/darrow-artificer/backend pytest plugins/automation/darrow-artificer/backend/tests passed 130 tests on each; primary quality run used Python 3.13.14.
• bun run lint, bun run lint:ts, bun run lint:shell, bun run typecheck, bun run check:decisions bun run check:docs and bun run check:docs:external passed (95 external URLs).
• bash .agents/skills/darrow-guide/evals/fixtures/setup.test.sh and /bin/bash .agents/skills/darrow-guide/evals/fixtures/setup.test.sh passed (Bash 3.2.57; Bash 5 unavailable).
• Both finished skills passed frozen inspect-skill inspect; both changed plugins passed claude plugin validate.
• Seven explicit Artificer cases passed focused Codex live trials and dry preparation; Claude status, recovery and revocation passed. Codex unattended-grant and ordinary recipe-options regressions passed. Guide recipe/layer/visual cases passed on both native hosts. No implicit-positive trials were requested.
• From the new backend, uv run --quiet --frozen --no-dev python tests/live_native.py, tests/live_schedule.py and tests/live_delivery.py passed: encrypted restoration, retained parent/child history and routes, real launchd execution, and exact whitespace-bearing replies at WIP zero.

Detailed evidence, commands, native IDs, diagnosed failures and independent review.

Review notes

Focus review on native identity/credential handling, admission correlation and conservative recovery. The fresh independent artifact challenge found and verified repairs for archive expiry stranding open PRs, false cancellation status, and read-only eval state escaping the assertions.

Execution support is macOS + Codex CLI 0.154.0; Claude can manage Artificer or invoke the ordinary human recipe, but unattended Claude execution is not supported. No real GitHub ticket-to-PR delivery, deliberate Desktop-close event, forced native token refresh or real subscription exhaustion was exercised; the live transport probe used isolated GitHub/recipe fixtures. These limits are explicit in the evidence, so this PR references rather than automatically closes #157. Account setup requires no paid credits or automatic reload. No Artificer schedule was enabled for this repository; temporary probe schedules were removed.

Checklist

• I have read and followed CONTRIBUTING.md, including the contribution
  licensing terms.
• I added or updated the applicable invariant before implementation, or
  this change does not affect a capability invariant.
• I added or updated colocated evals, or this change does not affect skill
  behavior.
• I confirmed that each changed plugin remains self-contained, or this
  change does not affect plugin content.
• I ran bun run check:python, or this change does not affect registered
  Python packages or their repository quality infrastructure.