Cockpit readiness: implement path-aware Readiness Health scoring

[smota]

Background & Problem Statement

Epic: #156

Readiness/health scoring must not penalize roles/checks intentionally skipped by risk/profile path.

Proposed Solution

Update readiness health to calculate against applicable checks only and expose denominator/explanation.

Requirements

• Score dimensions: scope clarity, path fit, role flow completion, validation, review readiness, follow-up hygiene, version impact.
• Denominator excludes skipped-by-path and not-applicable checks.
• Dimension details explain included/excluded checks.
• Grade labels: healthy, needs-attention, blocked.

Acceptance criteria

• Health score excludes skipped/not-applicable checks.
• Details explain score composition and denominator.
• Bounded docs-only example can score healthy without architecture role.
• High-assurance example is blocked without human gate.

Test plan

• Unit tests for score denominator.
• Fixture tests for bounded, standard, high-assurance.
• UI tests for health detail panel.

Workflow classification

Domain/testing issue.

[github-actions]

Integrated into development by PR #155: #155

Merge commit: aefe4d9f7d159ccf04d29a4490c4b1c40269e81c
Release/promotion to main is tracked separately.