Adopt agentic-sdlc 4.9.0 #125

Outcome

Adopt published agentic-sdlc v4.9.0 in godot-devkit.

Done when

• Current plugin, model guide, and CI action references use the v4.9.0 release.
• Existing check inputs and repo behavior stay intact.
• CI passes on the adoption PR.

Plan

• Confirm the release tag and inspect its migration notes.
• Update current release references and any removed action interface.
• Run focused validation and inspect the diff.
• Merge the PR after CI and review pass.

Files

Plugin, model guide, and legacy agentic-sdlc CI checks: .claude/settings.json, AGENTS.md, .github/workflows/*.yml.

Proof

Parse settings JSON, inspect action references, run repository gate, and verify PR CI.

Tier

judgment

Authorization

Chris requested all studio projects adopt v4.9.0 on 2026-10-13.