Share readable blocked-trust explanations across test preflight output #2618

Goal

Use one plain-English explanation for blocked manifest-command trust in workspace test preflight and individual project command diagnostics.

Background

PR #2613 extracted project_test_trust_status() so workspace and individual project tests share trust-identity and status evaluation. Workspace preflight still formats manifest command trust is blocked (<reason>), while print_blocked_command_text() describes missing approval or a changed contract in plain English. The remaining difference is low-priority output polish; trust enforcement is already shared.

Scope

• Extract a pure blocked-trust explanation formatter in base_setup.manifest_trust_guidance.
• Reuse it from workspace test preflight and the detailed blocked-command renderer.
• Preserve each renderer's layout, command review guidance, and trust enforcement.

Acceptance Criteria

• Missing approval, changed manifest, and changed declared test requirements produce a shared, readable explanation in both paths.
• Workspace output remains concise and individual command output retains its identity and review/allow guidance.
• Trust decisions, exit behavior, and structured status fields retain their existing semantics; the existing detail string is presentation text.
• Focused validation covers both renderers for the relevant trust reasons and verifies workspace preflight still starts no tests when blocked.

Validation

• Run the focused workspace-test and trust-command Python tests.
• Run the existing manifest-command-trust BATS coverage and full Base test gate.
• Run the Stable compatibility check, relevant Python lint, and git diff --check.

Non-Goals

• Change trust identities, storage, approval rules, command execution, or JSON schema.
• Combine the compact workspace renderer with the full individual-command diagnostic.
• Broaden this follow-up into general trust UX redesign.

Project Fields

• Status: In Progress
• Priority: P3
• Area: CLI
• Initiative: Adoption Polish
• Size: S
• Milestone: v1.11.0

Agent Assignment

Assigned to codeforester. Codex will implement one focused issue-backed PR and leave it open for review.