feat: implement AI Agent Integration & Actionable JSON Schema (Phase 16)

[jmrenouard]

Implement AI Agent Integration & Actionable JSON Schema support.

• Add --agent-json flag returning a structured, machine-actionable JSON payload.
• Mapped tuning recommendations to safe SQL/Config statements and rollback commands.
• Configured expected outcomes, risk assessments, and impact scores.

[jmrenouard]

The implementation is delivered in the following branch: https://github.com/jmrenouard/MySQLTuner-perl/tree/v2.9.1

[jmrenouard]

Hey everyone! 🎉

Phase 16 (AI Agent Integration & Actionable JSON Schema) is officially completed, merged into master via PR #963, and released in v2.9.1!

Summary of features:

• Introduced the --agent-json CLI option which outputs a machine-readable, structured JSON payload adhering to the actionable schema specification.
• Every diagnostic indicator maps directly to executable SQL/configuration statements, safe rollback statements, risk level assessments, impact scoring, and restart requirement flags.
• Validated via tests/unit_agent_json.t and integration tests.

Closing this issue as delivered. Thanks for your support! 🤖✨