[WIP] Add CI artifact guidance for Anki Factory smoke reports

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

---

This section details on the original issue you should resolve

<issue_title>[Anki Factory]: document CI smoke artifact review workflow</issue_title>
<issue_description>## Summary
Add CI artifact guidance for comparing Anki Factory smoke reports across PRs.

Scope

• Public-safe CI/reporting only.
• No private generated decks or local run artifacts.
• Target files: .github/workflows/anki-factory-ci.yml, docs/anki-factory/copilot-operation.md, and tools/anki-factory/scripts/validate_copilot_integration.py.

Expected Change

Document how reviewers should read the uploaded anki-factory-smoke-report artifact and use it to compare fixture, integration, and agent eval results.

Acceptance Criteria

• CI still uploads anki-factory-smoke-report.
• The integration validator fails if artifact upload is removed.
• Documentation explains what fixture_gate, copilot_integration_gate, and agent_eval_gate mean.
  </issue_description>

Comments on the Issue (you are @copilot in this section)

[dldydghk03]

@copilot Please proceed with a narrow implementation for issue #8.

Scope:

• Only public-safe CI/docs/validator changes.
• Do not add private deck output, local APKG artifacts, or personal paths.
• Target docs/anki-factory/copilot-operation.md and tools/anki-factory/scripts/validate_copilot_integration.py; only touch .github/workflows/anki-factory-ci.yml if the existing artifact upload check needs a small wording or validation adjustment.

Acceptance:

• Document how reviewers should read the uploaded anki-factory-smoke-report artifact.
• Explicitly explain fixture_gate, copilot_integration_gate, and agent_eval_gate.
• Keep .github/skills/anki-factory-quality/scripts/run-smoke.sh passing.
• Keep the integration validator failing if the smoke artifact upload is removed.