feat: promote domain coverage P3 to official release

[mrgoonie]

Problem Statement

The Domain Coverage P3 CLI fillers have passed beta validation on dev and need promotion to the official main release stream.

Proposal

Promote the verified dev changes to main so the release workflow publishes the stable v0.6.0 line.

How It Works

• Merge the P3 CLI coverage changes from dev into main.
• Run local Go test, vet, build, and diff hygiene gates before PR.
• Let the main push release workflow generate the official stable release and changelog asset.

Plan & Phases

• Beta release verified on dev
• Local tests passing on release branch
• Release PR prepared
• PR merged to main
• Stable release published

Human Review Tasks

• Verify release notes are acceptable
• Confirm stable release assets after merge