[Phase 12] Add recovery plans and enforce conflict-mode policy

[cosentinode]

Scope

Add typed recovery requests/plans, high-risk confirmations, centralized conflict-mode allowlisting, blocking for unrelated risky operations, execution-time state revalidation, and sanitized audit names.

Acceptance Criteria

• Continue/abort/skip plans are high risk and require uppercase Y; merge has no skip.
• Prompt sequences with blocked operations fail before any side effect.
• State changes after preview block execution.
• Status/diff/staging required for resolution remain available.
• Recovery audit entries are stable and sanitized.

Verification

• cargo fmt --all --check
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo test --locked --workspace

Notes

Child of #14. Depends on typed state and Git recovery commands.