Add ready-for-dev issue and PR readiness gates

[neubig]

Add a repository-appropriate ready-for-dev workflow and CI enforcement for automation changes.

Scope:

• Add type-specific readiness checks for bugs and enhancements, tailored to automation reproducibility (for example pytest, uv, or the repository’s supported development commands).
• Ensure not-ready results do not abort workflow processing under set -euo pipefail.
• Add idempotent readiness feedback comments and label management.
• Add a PR description gate for linked issues and refresh it when ready-for-dev changes.
• Add tests using the repository’s existing Python test tooling.

Acceptance criteria:

• Not-ready issues still receive feedback and correct label updates.
• Linked PRs are blocked until their issue is ready.
• Label transitions refresh linked PR checks.
• CI and tests pass.

This issue was created by an AI agent (OpenHands) on behalf of the user.

[neubig]

Draft PR opened: #380

Implements all four acceptance criteria:

• Not-ready issues receive an upserted feedback comment and correct label transitions (not-ready never aborts the workflow under set -euo pipefail — --json mode exits 0).
• Linked PRs are blocked by the new PR Description Check until each linked issue carries ready-for-dev (pre-rollout issues grandfathered).
• ready-for-dev label transitions re-run the gate on every linked open PR via the refresh-linked-pr-gates job.
• 30 new pytest tests; CI green.

This comment was created by an AI agent (OpenHands) on behalf of the user.

[VascoSch92]

This is a test